Allopurinol interactions

Allopurinol (Zyloprim, Aloprim), a xanthine oxidase inhibitor has 301 documented interactions across the FDA labels and fact sheets we index: 11 major, 272 moderate, 12 minor, and 6 where a label reports no significant interaction. Each entry below quotes the sentence behind it. This drug page is a starting point, not a verdict for your situation.

What Allopurinol looks like

All 33 versions
Allopurinol 100 mg tablet: white, round, 3 mm, scored, imprinted ZYLOPRIM on one side and 100 on the other.
ZYLOPRIM / 100
100 mg · white · round · 3 mm · scored
Prometheus
Allopurinol 300 mg tablet: orange, round, 4 mm, scored, imprinted ZYLOPRIM on one side and 300 on the other.
ZYLOPRIM / 300
300 mg · orange · round · 4 mm · scored
Prometheus
Allopurinol 100 mg tablet: white, capsule-shaped, 8 mm, scored, imprinted I on one side and 135 on the other.
I / 135
100 mg · white · capsule-shaped · 8 mm · scored
Florida Pharmaceutical Pro…
Allopurinol 300 mg tablet: pink, capsule-shaped, 11 mm, scored, imprinted I on one side and 136 on the other.
I / 136
300 mg · pink · capsule-shaped · 11 mm · scored
Florida Pharmaceutical Pro…

Renderings from the FDA labels' product listings: color, shape, size, and imprint. 33 documented versions from 27 labelers.

Interactions from the label

Major interactions (11)

  • AdenosineantiarrhythmicMajor

    Use of methylxanthines (e.g., caffeine, aminophylline and theophylline) is not recommended in patients who experience a seizures in association with adenosine injection ( 5.6 ) (Adenosine label, Warnings and precautions)

  • However, there may be an increased risk of severe skin toxicity when bendamustine hydrochloride and allopurinol are administered concomitantly. [see Warnings and Precautions (5.6) ] 5.6 Skin Reactions Fatal and serious skin reactions have been reported with bendamustine hydrochloride injection treatment in clinical trials and postmarketing safety reports, including… (Bendamustine label, Warnings and precautions)

  • CapecitabineantimetaboliteMajor

    Capecitabine: Avoid concomitant use. (Allopurinol label, Drug interactions)

  • CiprofloxacinfluoroquinoloneMajor

    Serious Adverse Reactions with Concomitant Theophylline Serious and fatal reactions have been reported in patients receiving concurrent administration of ciprofloxacin and theophylline. (Ciprofloxacin label, Warnings and precautions)

  • Deferasiroxiron supplementMajor

    Avoid the use of Exjade with CYP1A2 substrate theophylline. (Deferasirox label, Drug interactions)

  • EpinephrinesympathomimeticMajor

    …hormones Diuretics Cardiac glycosides, such as digitalis glycosides Quinidine Drugs potentiating hypokalemic effects of epinephrine • Potassium depleting diuretics • Corticosteroids • Theophylline Epinephrine should not be used to counteract circulatory collapse or hypotension caused by phenothiazines, as a reversal of the pressor effects of epinephrine may result… (Epinephrine label, Drug interactions)

  • Febuxostatxanthine oxidase inhibitorMajor

    WARNING: CARDIOVASCULAR DEATH Gout patients with established cardiovascular (CV) disease treated with ULORIC had a higher rate of CV death compared to those treated with allopurinol in a CV outcomes study [see Warnings and Precautions (5.1) ] . (Febuxostat label, Boxed warning)

  • FluorouracilantimetaboliteMajor

    Intervention Concomitant administration with fluorouracil should be avoided. (Allopurinol label, Drug interactions)

  • KetamineCNS depressantMajor

    Theophylline or Aminophylline : Do not co-administer with KETALAR as concomitant use may lower the seizure threshold ( 7.1 ). (Ketamine label, Drug interactions)

  • RifampinantibioticMajor

    Quinine Prevention or Management : Avoid concomitant use Decrease AUC by 75%-85% Telithromycin Decrease AUC by 86% Theophylline Decrease exposure by 20%-40% Effect of Other Drugs on Rifampin Concomitant antacid administration may reduce the absorption of rifampin. (Rifampin label, Drug interactions)

  • RiociguatvasodilatorMajor

    Phosphodiesterase Inhibitors Concomitant administration of Adempas with specific PDE-5 inhibitors (such as sildenafil, tadalafil, or vardenafil) or nonspecific PDE-5 inhibitors (such as dipyridamole or theophylline) is contraindicated [see Dosage and Administration (2.6), Drug Interactions ( 7.1 ) and Clinical Pharmacology ( 12.2 )]. (Riociguat label, Contraindications)

Moderate interactions (272)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Acetazolamidecarbonic anhydrase inhibitorModerate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • AclidiniumanticholinergicModerate

    Sympathomimetics, Methylxanthines, Steroids In clinical studies, concurrent administration of aclidinium bromide and other drugs commonly used in the treatment of COPD including sympathomimetics (short-acting beta 2 agonists), methylxanthines, and oral and inhaled steroids showed no increases in adverse drug reactions. (Aclidinium label, Drug interactions)

  • AdalimumabimmunosuppressantModerate

    Upon initiation or discontinuation of Adalimumab-fkjp in patients being treated with CYP450 substrates with a narrow therapeutic index, monitoring of the effect (e.g., warfarin) or drug concentration (e.g., cyclosporine or theophylline) is recommended and the individual dose of the drug product may be adjusted as needed. (Adalimumab label, Drug interactions)

  • AlbendazoleModerate

    Theophylline: Albendazole induces cytochrome P450 1A in human hepatoma cells; therefore, it is recommended that plasma concentrations of theophylline be monitored during and after treatment. (Albendazole label, Drug interactions)

  • AlcoholAlcoholModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • AlprazolambenzodiazepineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Amiloridepotassium-sparing diureticModerate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • AminophyllinemethylxanthineModerate

    30% increase Allopurinol Decreases theophylline clearance at allopurinol doses ≥600 mg/day. (Aminophylline label, Drug interactions)

  • Amitriptylinetricyclic antidepressantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Amoxapinetricyclic antidepressantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Amoxicillinpenicillin antibioticModerate

    Concomitant use of the following drugs may also increase the risk of skin rash, which may be severe: bendamustine, ampicillin and amoxicillin [ see Drug Interactions (7.1) ]. (Allopurinol label, Warnings and precautions)

  • Amoxicillin and clavulanatepenicillin antibioticModerate

    Concomitant use of the following drugs may also increase the risk of skin rash, which may be severe: bendamustine, ampicillin and amoxicillin [ see Drug Interactions (7.1) ]. (Allopurinol label, Warnings and precautions)

  • Ampicillinpenicillin antibioticModerate

    Concomitant use of the following drugs may also increase the risk of skin rash, which may be severe: bendamustine, ampicillin and amoxicillin [ see Drug Interactions (7.1) ]. (Allopurinol label, Warnings and precautions)

  • Ampicillin and sulbactampenicillin antibioticModerate

    Concomitant use of the following drugs may also increase the risk of skin rash, which may be severe: bendamustine, ampicillin and amoxicillin [ see Drug Interactions (7.1) ]. (Allopurinol label, Warnings and precautions)

  • ApixabananticoagulantModerate

    Dicumarol Clinical Impact Allopurinol tablets prolongs the half-life of the anticoagulant, dicumarol. (Allopurinol label, Drug interactions)

  • Arformoterolbeta-adrenergic agonistModerate

    Xanthine derivatives, steroids, diuretics, or non-potassium sparing diuretics may potentiate hypokalemia or ECG changes. (Arformoterol label, Drug interactions)

  • ArgatrobananticoagulantModerate

    Dicumarol Clinical Impact Allopurinol tablets prolongs the half-life of the anticoagulant, dicumarol. (Allopurinol label, Drug interactions)

  • AripiprazoleantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • AsenapineantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Atenolol and chlorthalidonebeta blockerModerate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • AzathioprineimmunosuppressantModerate

    Concomitant use with allopurinol increases the exposure of either mercaptopurine or azathioprine which may increase the risk of myelosuppression. (Allopurinol label, Warnings and precautions)

  • AzelastineantihistamineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Azelastine and fluticasoneantihistamineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Baclofenmuscle relaxantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Belladonna and opiumopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • BivalirudinanticoagulantModerate

    Dicumarol Clinical Impact Allopurinol tablets prolongs the half-life of the anticoagulant, dicumarol. (Allopurinol label, Drug interactions)

  • BleomycinModerate

    Cyclophosphamide and Other Cytotoxic Agents Clinical Impact Concomitant use of allopurinol with cyclophosphamide and other cytotoxic agents (doxorubicin, bleomycin, procarbazine, mechloroethamine) increases bone marrow suppression among patients with neoplastic disease, except leukemia. (Allopurinol label, Drug interactions)

  • BrexpiprazoleantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • BrivaracetamanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Bumetanideloop diureticModerate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • BuprenorphineopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • BupropionantidepressantModerate

    …also increase the risk of seizure: concomitant use of other medications that lower the seizure threshold (e.g., other bupropion products, antipsychotics, tricyclic antidepressants, theophylline, and systemic corticosteroids), metabolic disorders (e.g., hypoglycemia, hyponatremia, severe hepatic impairment, and hypoxia), or use of illicit drugs (e.g., cocaine)… (Bupropion label, Warnings and precautions)

  • Butalbital and acetaminophenbarbiturateModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • ButorphanolopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Candesartan and hydrochlorothiazideangiotensin II receptor blocker (ARB)Moderate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • Cannabidiol (prescription)anticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • CarbamazepineanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • CarbinoxamineantihistamineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • CariprazineantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Carisoprodolmuscle relaxantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • CenobamateanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • CetirizineantihistamineModerate

    There was a small decrease in the clearance of oral cetirizine hydrochloride caused by a 400-mg dose of theophylline; it is possible that larger theophylline doses could have a greater effect [see Clinical Pharmacology ( 12.3 )]. (Cetirizine label, Drug interactions)

  • ChlordiazepoxidebenzodiazepineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Chlordiazepoxide and clidiniumbenzodiazepineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Chlorothiazidethiazide diureticModerate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • ChlorpheniramineantihistamineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • ChlorpromazineantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Chlorthalidonethiazide diureticModerate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • Chlorzoxazonemuscle relaxantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • CimetidineH2 blockerModerate

    …apparently through an effect on certain microsomal enzyme systems, has been reported to reduce the hepatic metabolism of warfarin-type anticoagulants, phenytoin, propranolol, nifedipine, chlordiazepoxide, diazepam, certain tricyclic antidepressants, lidocaine, theophylline, and metronidazole, thereby delaying elimination and increasing blood levels of these drugs. (Cimetidine label, Drug interactions)

  • Clarithromycinmacrolide antibioticModerate

    Xanthine Derivatives: Theophylline Use With Caution Theophylline: Clarithromycin use in patients who are receiving theophylline may be associated with an increase of serum theophylline concentrations [see Pharmacokinetics ( 12.3 )] . (Clarithromycin label, Drug interactions)

  • ClemastineantihistamineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • ClobazambenzodiazepineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Clomipraminetricyclic antidepressantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • ClonazepambenzodiazepineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Clonidinealpha-adrenergic agonistModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • ClorazepatebenzodiazepineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • ClozapineantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • CodeineopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • ColchicineModerate

    In order to prevent gout flares when treatment with allopurinol tablets is initiated, concurrent prophylactic treatment with colchicine or an anti-inflammatory agent is recommended [ see Dosage and Administration (2.2) ]. (Allopurinol label, Warnings and precautions)

  • Cyclobenzaprinemuscle relaxantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • CyclophosphamideimmunosuppressantModerate

    Cyclophosphamide and Other Cytotoxic Agents Clinical Impact Concomitant use of allopurinol with cyclophosphamide and other cytotoxic agents (doxorubicin, bleomycin, procarbazine, mechloroethamine) increases bone marrow suppression among patients with neoplastic disease, except leukemia. (Allopurinol label, Drug interactions)

  • CyclosporineimmunosuppressantModerate

    Cyclosporine Clinical Impact Concomitant use of allopurinol increases cyclosporine concentrations, which may increase the risk of adverse reactions. (Allopurinol label, Drug interactions)

  • CyproheptadineantihistamineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • DabigatrananticoagulantModerate

    Dicumarol Clinical Impact Allopurinol tablets prolongs the half-life of the anticoagulant, dicumarol. (Allopurinol label, Drug interactions)

  • Dantrolenemuscle relaxantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Daridorexantsedative-hypnoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Desfluranegeneral anestheticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Desipraminetricyclic antidepressantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Desogestrel and ethinyl estradioloral contraceptiveModerate

    Effects of Combined Hormonal Contraceptives on Other Drugs COCs containing EE may inhibit the metabolism of other compounds (e.g., cyclosporine, prednisolone, theophylline, tizanidine, and voriconazole) and increase their plasma concentrations. (Desogestrel and ethinyl estradiol label, Drug interactions)

  • DexchlorpheniramineantihistamineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Dexmedetomidinealpha-adrenergic agonistModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • DiazepambenzodiazepineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Dichlorphenamidecarbonic anhydrase inhibitorModerate

    Drugs that Cause Hypokalemia The risk of hypokalemia is greater with coadministration of KEVEYIS and other drugs that can cause hypokalemia (e.g., loop diuretics, thiazide diuretics, laxatives, antifungals, penicillins, and theophylline) [see Warnings and Precautions (5.3) ] . (Dichlorphenamide label, Drug interactions)

  • DimenhydrinateantihistamineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • DiphenhydramineantihistamineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Divalproex (valproate)anticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • DoxapramModerate

    There may be an interaction between doxapram and aminophylline and between doxapram and theophylline manifested by increased skeletal muscle activity, agitation, and hyperactivity. (Doxapram label, Drug interactions)

  • Doxepintricyclic antidepressantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • DoxorubicinModerate

    Cyclophosphamide and Other Cytotoxic Agents Clinical Impact Concomitant use of allopurinol with cyclophosphamide and other cytotoxic agents (doxorubicin, bleomycin, procarbazine, mechloroethamine) increases bone marrow suppression among patients with neoplastic disease, except leukemia. (Allopurinol label, Drug interactions)

  • DoxylamineantihistamineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Doxylamine and pyridoxineantihistamineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • DronabinolcannabinoidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Droperidoldopamine antagonistModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Drospirenone and ethinyl estradioloral contraceptiveModerate

    …studies, administration of a hormonal contraceptive containing EE did not lead to any increase or only to a weak increase in plasma concentrations of CYP3A4 substrates (e.g., midazolam) while plasma concentrations of CYP2C19 substrates (e.g., omeprazole and voriconazole) and CYP1A2 substrates (e.g., theophylline and tizanidine) can have a weak or moderate increase. (Drospirenone and ethinyl estradiol label, Drug interactions)

  • Dutasteride and tamsulosin5-alpha reductase inhibitorModerate

    Tamsulosin Dosage adjustments are not necessary when tamsulosin is administered concomitantly with digoxin or theophylline [see Clinical Pharmacology (12.3) ]. (Dutasteride and tamsulosin label, Drug interactions)

  • EdoxabananticoagulantModerate

    Dicumarol Clinical Impact Allopurinol tablets prolongs the half-life of the anticoagulant, dicumarol. (Allopurinol label, Drug interactions)

  • EluxadolineopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • EnoxaparinanticoagulantModerate

    Dicumarol Clinical Impact Allopurinol tablets prolongs the half-life of the anticoagulant, dicumarol. (Allopurinol label, Drug interactions)

  • Eplerenonealdosterone antagonistModerate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • Erythromycinmacrolide antibioticModerate

    Drug Interactions Theophylline Erythromycin use in patients who are receiving high doses of theophylline may be associated with an increase in serum theophylline levels and potential theophylline toxicity. (Erythromycin label, Drug interactions)

  • EslicarbazepineanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • EstazolambenzodiazepineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Eszopiclonesedative-hypnoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Ethacrynic acidloop diureticModerate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • EthosuximideanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Etomidategeneral anestheticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Effects of CHCs on Other Drugs CHCs containing ethinyl estradiol may inhibit the metabolism of other compounds (e.g., cyclosporine, prednisolone, theophylline, tizanidine, and voriconazole) and increase their plasma concentrations. (Etonogestrel and ethinyl estradiol label, Drug interactions)

  • FelbamateanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • FentanylopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • FlibanserinCNS depressantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Fluconazoleazole antifungalModerate

    (See CLINICAL PHARMACOLOGY: Drug Interaction Studies .) Theophylline Fluconazole increases the serum concentrations of theophylline. (Fluconazole label, Drug interactions)

  • FlumazenilbenzodiazepineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • FluphenazineantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • FluvoxamineSSRIModerate

    Theophylline: Clearance decreased; reduce theophylline dose by one-third ( 5.8 ). (Fluvoxamine label, Warnings and precautions)

  • FondaparinuxanticoagulantModerate

    Dicumarol Clinical Impact Allopurinol tablets prolongs the half-life of the anticoagulant, dicumarol. (Allopurinol label, Drug interactions)

  • Formoterolbeta-adrenergic agonistModerate

    • Xanthine derivatives, steroids, diuretics, or non-potassium sparing diuretics may potentiate hypokalemia or ECG changes. (Formoterol label, Drug interactions)

  • Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • FosphenytoinanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Furosemideloop diureticModerate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • GabapentinanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Guanfacinealpha-adrenergic agonistModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • HaloperidolantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • HeparinanticoagulantModerate

    Dicumarol Clinical Impact Allopurinol tablets prolongs the half-life of the anticoagulant, dicumarol. (Allopurinol label, Drug interactions)

  • Hydrochlorothiazidethiazide diureticModerate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • HydrocodoneopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • HydromorphoneopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • HydroxyzineantihistamineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • IloperidoneantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Imipraminetricyclic antidepressantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Indapamidethiazide diureticModerate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • InfliximabimmunosuppressantModerate

    Upon initiation or discontinuation of RENFLEXIS in patients being treated with CYP450 substrates with a narrow therapeutic index, monitoring of the effect (e.g., warfarin) or drug concentration (e.g., cyclosporine or theophylline) is recommended and the individual dose of the drug product may be adjusted as needed. (Infliximab label, Drug interactions)

  • Irbesartan and hydrochlorothiazideangiotensin II receptor blocker (ARB)Moderate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • Isofluranegeneral anestheticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • IsoniazidantibioticModerate

    Theophylline A recent study has shown that concomitant administration of isoniazid and theophylline may cause elevated plasma levels of theophylline, and in some instances a slight decrease in the elimination of isoniazid. (Isoniazid label, Drug interactions)

  • LacosamideanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Lansoprazoleproton pump inhibitorModerate

    Theophylline Clinical Impact: Increased clearance of theophylline [see Clinical Pharmacology (12.3) ] . (Lansoprazole label, Drug interactions)

  • LeflunomideimmunosuppressantModerate

    In patients taking ARAVA, exposure of drugs metabolized by CYP1A2 (e.g., alosetron, duloxetine, theophylline, tizanidine) may be reduced. (Leflunomide label, Drug interactions)

  • Lemborexantsedative-hypnoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • LevetiracetamanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • LevocetirizineantihistamineModerate

    There was a small decrease (~16%) in the clearance of cetirizine caused by a 400 mg dose of theophylline. (Levocetirizine label, Drug interactions)

  • LevofloxacinfluoroquinoloneModerate

    However, concomitant administration of other fluoroquinolones with theophylline has resulted in prolonged elimination half-life, elevated serum theophylline levels, and a subsequent increase in the risk of theophylline-related adverse reactions in the patient population. (Levofloxacin label, Drug interactions)

  • Levonorgestrel and ethinyl estradioloral contraceptiveModerate

    Concomitant use with ethinyl estradiol-containing CHCs may increase systemic exposure of other drugs (e.g., cyclosporine, prednisolone, theophylline, tizanidine, and voriconazole). (Levonorgestrel and ethinyl estradiol label, Drug interactions)

  • LevorphanolopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • Lofexidinealpha-adrenergic agonistModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • LorazepambenzodiazepineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Losartan and hydrochlorothiazideangiotensin II receptor blocker (ARB)Moderate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • LoxapineantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • LumateperoneantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • LurasidoneantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • MeclizineantihistamineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • MeperidineopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • MeprobamateCNS depressantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • MercaptopurineantimetaboliteModerate

    Concomitant use with allopurinol increases the exposure of either mercaptopurine or azathioprine which may increase the risk of myelosuppression. (Allopurinol label, Warnings and precautions)

  • Metaxalonemuscle relaxantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • MethadoneopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Methimazoleantithyroid drugModerate

    Theophylline: Theophylline clearance may decrease when hyperthyroid patients on a stable theophylline regimen become euthyroid; a reduced dose of theophylline may be needed. (Methimazole label, Drug interactions)

  • Methocarbamolmuscle relaxantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • MethohexitalbarbiturateModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • MethotrexateimmunosuppressantModerate

    Effect of XATMEP on Other Drugs Theophylline Methotrexate may decrease the clearance of theophylline. (Methotrexate label, Drug interactions)

  • MethsuximideanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Metoclopramidedopamine antagonistModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Metolazonethiazide diureticModerate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • MexiletineantiarrhythmicModerate

    Concurrent use of mexiletine and theophylline may lead to increased plasma theophylline levels. (Mexiletine label, Drug interactions)

  • MidazolambenzodiazepineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • MirtazapineantidepressantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • MorphineopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • NalbuphineopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Naltrexone and bupropionopioid antagonistModerate

    …may cause hypoglycemia concomitant administration of medications that may lower the seizure threshold, including other bupropion products, antipsychotics, tricyclic antidepressants, theophylline, systemic steroids Recommendations for Reducing the Risk of Seizure: Clinical experience with bupropion suggests that the risk of seizure may be minimized by adhering to… (Naltrexone and bupropion label, Warnings and precautions)

  • NefazodoneantidepressantModerate

    FEV 1 measurements taken when theophylline and nefazodone were coadministered did not differ from baseline dosage (i.e., when theophylline was administered alone). (Nefazodone label, Drug interactions)

  • NelarabineantimetaboliteModerate

    Consideration should be given to the use of allopurinol in patients at risk of hyperuricemia [see Dosage and Administration ( 2.4 )] . (Nelarabine label, Warnings and precautions)

  • Effects of Combined Hormonal Contraceptives on Other Drugs CHCs containing EE may inhibit the metabolism of other compounds (e.g., cyclosporine, prednisolone, theophylline, tizanidine, and voriconazole) and increase their plasma concentrations. (Norelgestromin and ethinyl estradiol label, Drug interactions)

  • Norgestimate and ethinyl estradioloral contraceptiveModerate

    Effects of Combined Oral Contraceptives on Other Drugs COCs containing EE may inhibit the metabolism of other compounds (e.g., cyclosporine, prednisolone, theophylline, tizanidine, and voriconazole) and increase their plasma concentrations. (Norgestimate and ethinyl estradiol label, Drug interactions)

  • Norgestrel and ethinyl estradioloral contraceptiveModerate

    Effects of Combined Oral Contraceptives on Other Drugs COCs containing EE may inhibit the metabolism of other drugs (e.g., cyclosporine, prednisolone, theophylline, tizanidine, and voriconazole) and increase their plasma concentrations. (Norgestrel and ethinyl estradiol label, Drug interactions)

  • Nortriptylinetricyclic antidepressantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • OfloxacinfluoroquinoloneModerate

    This may result in a prolonged half-life for some drugs that are also metabolized by this system (e.g., cyclosporine, theophylline/methylxanthines, warfarin) when coadministered with quinolones. (Ofloxacin label, Drug interactions)

  • OlanzapineantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Olanzapine and fluoxetineantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • OliceridineopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Olmesartan and hydrochlorothiazideangiotensin II receptor blocker (ARB)Moderate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • Olmesartan, amlodipine, and hydrochlorothiazideangiotensin II receptor blocker (ARB)Moderate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • Orphenadrinemuscle relaxantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • OxazepambenzodiazepineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • OxcarbazepineanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • OxycodoneopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • OxymorphoneopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • PaliperidoneantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • PerampanelanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • PerphenazineantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • PhenobarbitalbarbiturateModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Phentermine and topiramateCNS stimulantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • PhenytoinanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • PimavanserinantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • PimozideantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Pramipexoledopamine agonistModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • PregabalinanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • PrimaquineantimalarialModerate

    Effects of Primaquine on the Pharmacokinetics of Other Drugs CYP1A2 Substrates Published clinical and non-clinical reports indicate primaquine inhibits CYP1A2 enzyme activity and thus may lead to increased exposure of CYP1A2 substrate drugs (e.g., duloxetine, alosetron, theophylline and tizanidine) when co-administered with Primaquine phosphate Tablets. (Primaquine label, Drug interactions)

  • PrimidoneanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • In order to prevent gout flares when treatment with allopurinol tablets is initiated, concurrent prophylactic treatment with colchicine or an anti-inflammatory agent is recommended [ see Dosage and Administration (2.2) ]. (Allopurinol label, Warnings and precautions)

  • ProchlorperazineantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • PromethazineantihistamineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • PropofolCNS depressantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Propylthiouracilantithyroid drugModerate

    Theophylline: Theophylline clearance may decrease when hyperthyroid patients on a stable theophylline regimen become euthyroid; a reduced dose of theophylline may be needed. (Propylthiouracil label, Drug interactions)

  • Protriptylinetricyclic antidepressantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • QuetiapineantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • QuinineantimalarialModerate

    Theophylline or Aminophylline In 20 healthy subjects who received multiple doses of quinine sulfate (648 mg every 8 hours x 7 days) with a single 300 mg oral dose of theophylline, the quinine mean C max and AUC were increased by 13% and 14% respectively. (Quinine label, Drug interactions)

  • Ramelteonsedative-hypnoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • RemifentanilopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • RifapentineantibioticModerate

    …Clofibrate Oral Hypoglycemics Sulfonylureas (e.g., glyburide, glipizide) Hormonal Contraceptives/Progestins Ethinyl estradiol, levonorgestrel Immunosuppressants Cyclosporine, tacrolimus Methylxanthines Theophylline Narcotic analgesics Methadone Phosphodiesterase-5 (PDE-5) Inhibitors Sildenafil Thyroid preparations Levothyroxine Tricyclic antidepressants Amitriptyline,… (Rifapentine label, Drug interactions)

  • RisperidoneantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • RitonavirantiretroviralModerate

    Bronchodilator: theophylline ↓ theophylline Increased dosage of theophylline may be required; therapeutic monitoring should be considered. (Ritonavir label, Drug interactions)

  • RivaroxabananticoagulantModerate

    Dicumarol Clinical Impact Allopurinol tablets prolongs the half-life of the anticoagulant, dicumarol. (Allopurinol label, Drug interactions)

  • Ropiniroledopamine agonistModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • RufinamideanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • ScopolamineanticholinergicModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Sevofluranegeneral anestheticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Sodium oxybateCNS depressantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Spironolactonealdosterone antagonistModerate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • Spironolactone and hydrochlorothiazidealdosterone antagonistModerate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • SucralfateModerate

    Drug Interactions Some studies have shown that simultaneous sucralfate administration in healthy volunteers reduced the extent of absorption (bioavailability) of single doses of the following: cimetidine, digoxin, fluoroquinolone antibiotics, ketoconazole, l-thyroxine, phenytoin, quinidine, ranitidine, tetracycline, and theophylline. (Sucralfate label, Drug interactions)

  • Suvorexantsedative-hypnoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • TadalafilPDE5 inhibitorModerate

    When tadalafil was administered to subjects taking theophylline, a small augmentation (3 beats per minute) of the increase in heart rate associated with theophylline was observed. (Tadalafil label, Drug interactions)

  • Tamsulosinalpha blockerModerate

    Digoxin and Theophylline Dosage adjustments are not necessary when a tamsulosin hydrochloride capsule is administered concomitantly with digoxin or theophylline [see Clinical Pharmacology ( 12.3 )] . (Tamsulosin label, Drug interactions)

  • TapentadolopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Tasimelteonsedative-hypnoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Telmisartan and hydrochlorothiazideangiotensin II receptor blocker (ARB)Moderate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • TemazepambenzodiazepineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • TerbinafineantifungalModerate

    The influence of terbinafine on the pharmacokinetics of fluconazole, cotrimoxazole (trimethoprim and sulfamethoxazole), zidovudine or theophylline was not considered to be clinically significant. (Terbinafine label, Drug interactions)

  • TeriflunomideimmunosuppressantModerate

    In patients taking AUBAGIO, exposure of drugs metabolized by CYP1A2 (e.g., alosetron, duloxetine, theophylline, tizanidine) may be reduced. (Teriflunomide label, Drug interactions)

  • TetrabenazineVMAT2 inhibitorModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • TheophyllinemethylxanthineModerate

    Theophylline Clinical Impact Concomitant use of allopurinol doses greater than or equal to 600 mg/day may decrease the clearance of theophylline Intervention Monitor and adjust theophylline doses as reflected in the prescribing information. (Allopurinol label, Drug interactions)

  • ThioridazineantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • ThiothixeneantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • TiagabineanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • TiotropiumanticholinergicModerate

    Concomitant Respiratory Medications SPIRIVA RESPIMAT has been used concomitantly with short-acting and long-acting sympathomimetic (beta-agonists) bronchodilators, methylxanthines, oral and inhaled steroids, antihistamines, mucolytics, leukotriene modifiers, cromones, and anti-IgE treatment without increases in adverse reactions. (Tiotropium label, Drug interactions)

  • Tizanidinemuscle relaxantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • TocilizumabimmunosuppressantModerate

    Upon initiation or discontinuation of TOFIDENCE, in patients being treated with these types of medicinal products, perform therapeutic monitoring of effect (e.g., warfarin) or drug concentration (e.g., cyclosporine or theophylline) and the individual dose of the medicinal product adjusted as needed. (Tocilizumab label, Drug interactions)

  • TopiramateanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Torsemideloop diureticModerate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • TramadolopioidModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • TrazodoneantidepressantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Triamterenepotassium-sparing diureticModerate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • Triamterene and hydrochlorothiazidepotassium-sparing diureticModerate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • TriazolambenzodiazepineModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • TrifluoperazineantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Trimipraminetricyclic antidepressantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Valproic acidanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Valsartan and hydrochlorothiazideangiotensin II receptor blocker (ARB)Moderate

    Hypersensitivity reactions to allopurinol tablets may be increased in patients with decreased kidney function receiving thiazide diuretics and allopurinol tablets concurrently. (Allopurinol label, Warnings and precautions)

  • VareniclineModerate

    • Effect of Smoking Cessation on Other Drugs: Pharmacokinetics or pharmacodynamics of certain drugs (e.g., theophylline, warfarin, insulin) may be altered, necessitating dose adjustment. (Varenicline label, Drug interactions)

  • Verapamilcalcium channel blockerModerate

    Theophylline Verapamil may inhibit the clearance and increase the plasma levels of theophylline. (Verapamil label, Drug interactions)

  • VigabatrinanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • WarfarinanticoagulantModerate

    Assess INR frequently and adjust warfarin dosage accordingly when allopurinol is added to warfarin therapy. (Allopurinol label, Drug interactions)

  • Zafirlukastleukotriene receptor antagonistModerate

    Coadministration of zafirlukast (20 mg/day) or placebo at steady-state with a single dose of sustained release theophylline preparation (16 mg/kg) in 16 healthy boys and girls (6 through 11 years of age) resulted in no significant differences in the pharmacokinetic parameters of theophylline. (Zafirlukast label, Precautions)

  • Zaleplonsedative-hypnoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • ZileutonCYP1A2 inhibitorModerate

    Zileuton increases theophylline levels. (Zileuton label, Drug interactions)

  • ZiprasidoneantipsychoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • Zolpidemsedative-hypnoticModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

  • ZonisamideanticonvulsantModerate

    Inform patients also that the central nervous system depressant effects of allopurinol tablets may be additive to those of alcohol and other CNS depressants. (Allopurinol label, Warnings and precautions)

Minor mentions (12)

  • Acebutololbeta blockerMinor

    A bronchodilator, such as theophylline or a β2-stimulant, should be made available in advance with instructions concerning its use. (Acebutolol label, Warnings)

  • AnagrelideQT-prolonging drugMinor

    CYP1A2 substrates: AGRYLIN demonstrates limited inhibitory activity towards CYP1A2 in vitro and may alter the exposure of concomitant CYP1A2 substrates (e.g., theophylline, fluvoxamine, ondansetron). (Anagrelide label, Drug interactions)

  • CaptoprilACE inhibitorMinor

    In foreign marketing experience in patients with renal failure, use of allopurinol concomitantly with captopril has been associated with neutropenia but this association has not appeared in U.S. reports. (Captopril label, Warnings)

  • CidofovirantiviralMinor

    …Probenecid Probenecid is known to interact with the metabolism or renal tubular excretion of many drugs (e.g., acetaminophen, acyclovir, angiotensin-converting enzyme inhibitors, aminosalicylic acid, barbiturates, benzodiazepines, bumetanide, clofibrate, methotrexate, famotidine, furosemide, nonsteroidal anti-inflammatory agents, theophylline, and zidovudine). (Cidofovir label, Drug interactions)

  • Hydration, urine alkalinization, and prophylaxis with allopurinol to prevent hyperuricemia may minimize potential complications of tumor lysis syndrome. (Idarubicin label, Warnings and precautions)

  • IpratropiumanticholinergicMinor

    ATROVENT HFA has been used concomitantly with other drugs, including sympathomimetic bronchodilators, methylxanthines, oral and inhaled steroids commonly used in the treatment of COPD. (Ipratropium label, Drug interactions)

  • Lithiumserotonergic drugMinor

    Acetazolamide, Urea, Xanthine Preparations, Alkalinizing Agents Clinical Impact: Concomitant use can lower serum lithium concentrations by increasing urinary lithium excretion. (Lithium label, Drug interactions)

  • Prazosinalpha blockerMinor

    …digoxin; (2) hypoglycemics–insulin, chlorpropamide, phenformin, tolazamide, and tolbutamide; (3) tranquilizers and sedatives–chlordiazepoxide, diazepam, and phenobarbital; (4) antigout–allopurinol, colchicine, and probenecid; (5) antiarrhythmics–procainamide, propranolol (see WARNINGS however), and quinidine; and (6) analgesics, antipyretics and anti-inflammatories–propoxyphene,… (Prazosin label, Drug interactions)

  • Falsely high readings for theophylline have been reported in an in vitro study, using the Schack and Waxler technique, when therapeutic concentrations of theophylline and probenecid were added to human plasma. (Probenecid label, Drug interactions)

  • Hepatotoxic Drugs Clinical trials in ALS patients excluded patients on concomitant medications which were potentially hepatotoxic (e.g., allopurinol, methyldopa, sulfasalazine). (Riluzole label, Drug interactions)

  • Ropivacainelocal anestheticMinor

    Possible interactions with drugs known to be metabolized by CYP1A2 via competitive inhibition such as theophylline and imipramine may also occur. (Ropivacaine label, Drug interactions)

  • Sixteen (16) drugs tested did not show an in vitro interaction with LOKELMA (allopurinol, apixaban, aspirin, captopril, cyclosporine, digoxin, ethinyl estradiol, lisinopril, magnesium, metformin, phenytoin, prednisone, propranolol, quinapril, spironolactone and ticagrelor). (Sodium zirconium cyclosilicate label, Drug interactions)

No significant interaction reported (6)

  • AlosetronNo interaction

    The effect on CYP1A2 was explored further in a clinical interaction study with theophylline and no effect on metabolism was observed. (Alosetron label, Drug interactions)

  • DofetilideantiarrhythmicNo interaction

    Other Drugs: In healthy volunteers, amlodipine, phenytoin, glyburide, ranitidine, omeprazole, hormone replacement therapy (a combination of conjugated estrogens and medroxyprogesterone), antacid (aluminum and magnesium hydroxides), and theophylline did not affect the pharmacokinetics of dofetilide. (Dofetilide label, Drug interactions)

  • FamciclovirantiviralNo interaction

    …Penciclovir No clinically significant alterations in penciclovir pharmacokinetics were observed following single-dose administration of 500 mg famciclovir after pretreatment with multiple doses of allopurinol, cimetidine, theophylline, zidovudine, promethazine, when given shortly after an antacid (magnesium and aluminum hydroxide), or concomitantly with emtricitabine. (Famciclovir label, Drug interactions)

  • Finasteride5-alpha reductase inhibitorNo interaction

    Compounds that have been tested in man have included antipyrine, digoxin, propranolol, theophylline, and warfarin and no clinically meaningful interactions were found. (Finasteride label, Drug interactions)

  • Montelukastleukotriene receptor antagonistNo interaction

    No dose adjustment is needed when SINGULAIR is co-administered with theophylline, prednisone, prednisolone, oral contraceptives, fexofenadine, digoxin, warfarin, gemfibrozil, itraconazole, thyroid hormones, sedative hypnotics, non-steroidal anti-inflammatory agents, benzodiazepines, decongestants, and Cytochrome P450 (CYP) enzyme inducers [see Clinical Pharmacology… (Montelukast label, Drug interactions)

  • NizatidineH2 blockerNo interaction

    Drug Interactions No interactions have been observed between nizatidine and theophylline, chlordiazepoxide, lorazepam, lidocaine, phenytoin, and warfarin. (Nizatidine label, Drug interactions)

Check Allopurinol against everything you take. Add your full list; every pair is checked at once.

Open in the checker

Not medical advice. Severity reflects the label's wording, not your circumstances. A "major" flag can be routine under supervision and a "minor" one can matter at high doses. Ask a pharmacist.