Phentermine interactions

Phentermine (Adipex-P, Lomaira), a CNS stimulant has 133 documented interactions across the FDA labels and fact sheets we index: 27 major, 81 moderate, 25 minor, and 0 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.

Major interactions (27)

  • Albuterolbeta-adrenergic agonistMajor

    …states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific Populations ( 8.3 ) ] • Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines • History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) () • During or within… (Phentermine label, Contraindications)

  • Hypersensitivity reactions such as angioedema and anaphylactic reactions have been reported in patients treated with other amphetamine products [see Adverse Reactions ( 6.2 )] . taking monoamine oxidase inhibitors (MAOIs), or within 14 days of stopping MAOIs (including MAOIs such as linezolid or intravenous methylene blue), because of an increased risk of hypertensive… (Amphetamine and dextroamphetamine label, Contraindications)

  • Budesonide and formoterolcorticosteroidMajor

    …states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific Populations ( 8.3 ) ] • Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines • History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) () • During or within… (Phentermine label, Contraindications)

  • DronabinolcannabinoidMajor

    Avoid concomitant use of other drugs that are also associated with similar cardiac effects (e.g., amphetamines, other sympathomimetic agents, atropine, amoxapine, scopolamine, antihistamines, other anticholinergic agents, amitriptyline, desipramine, other tricyclic antidepressants). (Dronabinol label, Warnings and precautions)

  • EpinephrinesympathomimeticMajor

    …states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific Populations ( 8.3 ) ] • Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines • History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) () • During or within… (Phentermine label, Contraindications)

  • Fluticasone and salmeterolcorticosteroidMajor

    …states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific Populations ( 8.3 ) ] • Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines • History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) () • During or within… (Phentermine label, Contraindications)

  • Formoterolbeta-adrenergic agonistMajor

    …states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific Populations ( 8.3 ) ] • Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines • History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) () • During or within… (Phentermine label, Contraindications)

  • HaloperidolantipsychoticMajor

    Should hypotension occur and a vasopressor be required, epinephrine must not be used since HALDOL DECANOATE may block its vasopressor activity, and paradoxically lower blood pressure. (Haloperidol label, Warnings and precautions)

  • IsoniazidantibioticMajor

    …cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) • During or within 14 days following the administration of monoamine oxidase inhibitors • Hyperthyroidism • Glaucoma • Agitated states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific… (Phentermine label, Contraindications)

  • Levalbuterolbeta-adrenergic agonistMajor

    …states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific Populations ( 8.3 ) ] • Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines • History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) () • During or within… (Phentermine label, Contraindications)

  • LinezolidantibioticMajor

    …cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) • During or within 14 days following the administration of monoamine oxidase inhibitors • Hyperthyroidism • Glaucoma • Agitated states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific… (Phentermine label, Contraindications)

  • Liothyroninethyroid hormoneMajor

    • Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects [see Adverse Reactions (6) , Drug Interactions (7.7) , and Overdosage (10) ] . (Liothyronine label, Boxed warning)

  • Mirabegronbeta-adrenergic agonistMajor

    …states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific Populations ( 8.3 ) ] • Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines • History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) () • During or within… (Phentermine label, Contraindications)

  • PhenelzineMAO inhibitorMajor

    …cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) • During or within 14 days following the administration of monoamine oxidase inhibitors • Hyperthyroidism • Glaucoma • Agitated states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific… (Phentermine label, Contraindications)

  • Phentermine and topiramateCNS stimulantMajor

    …(8.1) ] With glaucoma [see Warnings and Precautions (5.3) ] With hyperthyroidism Taking or within 14 days of stopping a monoamine oxidase inhibitors [see Drug Interactions (7) ] With known hypersensitivity to phentermine, topiramate or any of the excipients in phentermine and topiramate extended-release capsules, or idiosyncrasy to the sympathomimetic amines. (Phentermine and topiramate label, Contraindications)

  • PhenylephrinedecongestantMajor

    …states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific Populations ( 8.3 ) ] • Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines • History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) () • During or within… (Phentermine label, Contraindications)

  • PromethazineantihistamineMajor

    Epinephrine Because of the potential for Promethazine to reverse epinephrine's vasopressor effect, epinephrine should NOT be used to treat hypotension associated with Promethazine Syrup overdose. (Promethazine label, Drug interactions)

  • PseudoephedrinedecongestantMajor

    …states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific Populations ( 8.3 ) ] • Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines • History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) () • During or within… (Phentermine label, Contraindications)

  • RasagilineMAO inhibitorMajor

    …cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) • During or within 14 days following the administration of monoamine oxidase inhibitors • Hyperthyroidism • Glaucoma • Agitated states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific… (Phentermine label, Contraindications)

  • Salmeterolbeta-adrenergic agonistMajor

    …states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific Populations ( 8.3 ) ] • Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines • History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) () • During or within… (Phentermine label, Contraindications)

  • SelegilineMAO inhibitorMajor

    …cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) • During or within 14 days following the administration of monoamine oxidase inhibitors • Hyperthyroidism • Glaucoma • Agitated states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific… (Phentermine label, Contraindications)

  • Sodium oxybateCNS depressantMajor

    Many patients who received Xyrem during clinical trials in narcolepsy were receiving central nervous system stimulants [see Clinical Trials ( 14 )]. (Sodium oxybate label, Boxed warning)

  • Terbutalinebeta-adrenergic agonistMajor

    …states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific Populations ( 8.3 ) ] • Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines • History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) () • During or within… (Phentermine label, Contraindications)

  • Tizanidinemuscle relaxantMajor

    Hypotension: monitor for signs and symptoms of hypotension, in particular in patients receiving concurrent antihypertensives; Zanaflex should not be used with other α 2 -adrenergic agonists ( 5.1 , 7.7 ) (Tizanidine label, Warnings and precautions)

  • TranylcypromineMAO inhibitorMajor

    …cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) • During or within 14 days following the administration of monoamine oxidase inhibitors • Hyperthyroidism • Glaucoma • Agitated states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific… (Phentermine label, Contraindications)

  • Umeclidinium and vilanterolanticholinergicMajor

    …states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific Populations ( 8.3 ) ] • Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines • History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) () • During or within… (Phentermine label, Contraindications)

  • Vibegronbeta-adrenergic agonistMajor

    …states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific Populations ( 8.3 ) ] • Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines • History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) () • During or within… (Phentermine label, Contraindications)

Moderate interactions (81)

  • AcarboseantidiabeticModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • Acetazolamidecarbonic anhydrase inhibitorModerate

    Acetazolamide decreases urinary excretion of amphetamine and may enhance the magnitude and duration of their effect. (Acetazolamide label, Drug interactions)

  • 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)

  • AlcoholAlcoholModerate

    • Concomitant alcohol use may result in an adverse drug reaction. (Phentermine label, Warnings and precautions)

  • AlprazolambenzodiazepineModerate

    Prescribe the lowest effective dosage; avoid or minimize concomitant use of CNS depressants and other substances associated with abuse, misuse, and addiction (e.g., opioid analgesics, stimulants); and advise patients on the proper disposal of unused drug. (Alprazolam label, Warnings and precautions)

  • AmiodaroneantiarrhythmicModerate

    • Hypotension: Slow the infusion; as needed, add vasopressor drugs, positive inotropic agents, and volume expansion. (Amiodarone label, Warnings and precautions)

  • Amitriptylinetricyclic antidepressantModerate

    When amitriptyline is given with anticholinergic agents or sympathomimetic drugs, including epinephrine combined with local anesthetics, close supervision and careful adjustment of dosages are required. (Amitriptyline label, Drug interactions)

  • ArmodafinilCNS stimulantModerate

    Risk of Abuse and Dependence Phentermine is related chemically and pharmacologically to amphetamine (d- and d l l-amphetamine) and other related stimulant drugs that have been extensively abused. (Phentermine label, Warnings and precautions)

  • BupropionantidepressantModerate

    …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) or abuse or misuse of prescription drugs such as CNS stimulants. (Bupropion label, Warnings and precautions)

  • Butalbital, acetaminophen, and caffeinebarbiturateModerate

    Risk of Abuse and Dependence Phentermine is related chemically and pharmacologically to amphetamine (d- and d l l-amphetamine) and other related stimulant drugs that have been extensively abused. (Phentermine label, Warnings and precautions)

  • CanagliflozinSGLT2 inhibitorModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • Candesartanangiotensin II receptor blocker (ARB)Moderate

    Very rarely, hypotension may be severe such that it may warrant the use of intravenous fluids and/or vasopressors. (Candesartan label, Warnings and precautions)

  • ChlordiazepoxidebenzodiazepineModerate

    Prescribe the lowest effective dosage; avoid or minimize concomitant use of CNS depressants and other substances associated with abuse, misuse, and addiction (e.g., opioid analgesics, stimulants); and advise patients on the proper disposal of unused drug. (Chlordiazepoxide label, Warnings)

  • CitalopramSSRIModerate

    The risk is increased with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, meperidine, methadone, tryptophan, buspirone, amphetamines, and St. (Citalopram label, Warnings and precautions)

  • ClobazambenzodiazepineModerate

    Prescribe the lowest effective dosage; avoid or minimize concomitant use of CNS depressants and other substances associated with abuse, misuse, and addiction (e.g., opioid analgesics, stimulants); and advise patients on the proper disposal of unused drug. (Clobazam label, Warnings and precautions)

  • ClonazepambenzodiazepineModerate

    Prescribe the lowest effective dosage; avoid or minimize concomitant use of CNS depressants and other substances associated with abuse, misuse, and addiction (e.g., opioid analgesics, stimulants); and advise patients on the proper disposal of unused drug. (Clonazepam label, Warnings)

  • DapagliflozinSGLT2 inhibitorModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • DesvenlafaxineSNRIModerate

    The risk is increased with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, meperidine, methadone, tryptophan, buspirone, amphetamines, and St. (Desvenlafaxine label, Warnings and precautions)

  • DexmethylphenidateCNS stimulantModerate

    Risk of Abuse and Dependence Phentermine is related chemically and pharmacologically to amphetamine (d- and d l l-amphetamine) and other related stimulant drugs that have been extensively abused. (Phentermine label, Warnings and precautions)

  • DiazepambenzodiazepineModerate

    Prescribe the lowest effective dosage; avoid or minimize concomitant use of CNS depressants and other substances associated with abuse, misuse, and addiction (e.g., opioid analgesics, stimulants); and advise patients on the proper disposal of unused drug. (Diazepam label, Warnings)

  • DicyclomineanticholinergicModerate

    …drugs including dicyclomine hydrochloride: amantadine, antiarrhythmic agents of Class I (e.g., quinidine), antihistamines, antipsychotic agents (e.g., phenothiazines), benzodiazepines, MAO inhibitors, narcotic analgesics (e.g., meperidine), nitrates and nitrites, sympathomimetic agents, tricyclic antidepressants, and other drugs having anticholinergic activity. (Dicyclomine label, Drug interactions)

  • Digoxindigitalis glycosideModerate

    Sympathomimetics Epinephrine Can increase the risk of cardiac arrhythmias. (Digoxin label, Drug interactions)

  • Dorzolamide and timololcarbonic anhydrase inhibitorModerate

    If necessary during surgery, the effects of beta-adrenergic blocking agents may be reversed by sufficient doses of adrenergic agonists. (Dorzolamide and timolol label, Warnings and precautions)

  • DulaglutideGLP-1 receptor agonistModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • DuloxetineSNRIModerate

    The risk is increased with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, meperidine, methadone, tryptophan, buspirone, amphetamines, and St. (Duloxetine label, Warnings and precautions)

  • EmpagliflozinSGLT2 inhibitorModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • Empagliflozin and metforminSGLT2 inhibitorModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • EscitalopramSSRIModerate

    The risk is increased with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, meperidine, methadone, lithium, tramadol, tryptophan, buspirone, amphetamines, and St. (Escitalopram label, Warnings and precautions)

  • Esmololbeta blockerModerate

    Sympathomimetic drugs: Dose adjustment needed ( 7 ) (Esmolol label, Drug interactions)

  • ExenatideGLP-1 receptor agonistModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • FluoxetineSSRIModerate

    The risk is increased with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, tryptophan, meperidine, methadone, buspirone, amphetamines, and St. (Fluoxetine label, Warnings and precautions)

  • FluvoxamineSSRIModerate

    The risk is increased with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, meperidine, methadone, lithium, tramadol, tryptophan, buspirone, amphetamines, and St. (Fluvoxamine label, Warnings and precautions)

  • GlimepiridesulfonylureaModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • GlipizidesulfonylureaModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • GlyburidesulfonylureaModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • Glyburide and metforminsulfonylureaModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • Guanfacinealpha-adrenergic agonistModerate

    In these cases, high-dosage guanfacine was discontinued; concomitant stimulant use was also reported, which may potentially increase hypertensive response upon abrupt discontinuation of guanfacine. (Guanfacine label, Warnings and precautions)

  • Insulin aspartinsulinModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • Insulin degludecinsulinModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • Insulin detemirinsulinModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • Insulin glargineinsulinModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • Insulin lisproinsulinModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • Insulin regular (human)insulinModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • KetamineCNS depressantModerate

    Sympathomimetics and Vasopressin : Sympathomimetics and vasopressin may enhance the sympathomimetic effects of ketamine [see Drug Interactions ( 7.2 )] . (Ketamine label, Warnings and precautions)

  • LevomilnacipranSNRIModerate

    The risk is increased with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, meperidine, methadone, tryptophan, buspirone, amphetamines, and St. (Levomilnacipran label, Warnings and precautions)

  • Levothyroxinethyroid hormoneModerate

    Sympathomimetics Concurrent use may of sympathomimetics and levothyroxine may increase the effects of sympathomimetics or thyroid hormone. (Levothyroxine label, Drug interactions)

  • Lidocainelocal anestheticModerate

    Concurrent administration of vasopressor drugs (for the treatment of hypotension related to obstetric blocks) and ergot-type oxytocic drugs may cause severe, persistent hypertension or cerebrovascular accidents. (Lidocaine label, Drug interactions)

  • LinagliptinDPP-4 inhibitorModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • LiraglutideGLP-1 receptor agonistModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • LisdexamfetamineCNS stimulantModerate

    Risk of Abuse and Dependence Phentermine is related chemically and pharmacologically to amphetamine (d- and d l l-amphetamine) and other related stimulant drugs that have been extensively abused. (Phentermine label, Warnings and precautions)

  • LorazepambenzodiazepineModerate

    Prescribe the lowest effective dosage; avoid or minimize concomitant use of CNS depressants and other substances associated with abuse, misuse, and addiction (e.g., opioid analgesics, stimulants); and advise patients on the proper disposal of unused drug. (Lorazepam label, Warnings and precautions)

  • MetforminbiguanideModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • MethyldopaantihypertensiveModerate

    If hypotension does occur during anesthesia, it usually can be controlled by vasopressors. (Methyldopa label, Drug interactions)

  • MethylphenidateCNS stimulantModerate

    Risk of Abuse and Dependence Phentermine is related chemically and pharmacologically to amphetamine (d- and d l l-amphetamine) and other related stimulant drugs that have been extensively abused. (Phentermine label, Warnings and precautions)

  • Metolazonethiazide diureticModerate

    Sympathomimetics Metolazone may decrease arterial responsiveness to norepinephrine, but this diminution is not sufficient to preclude effectiveness of the pressor agent for therapeutic use. (Metolazone label, Drug interactions)

  • MirtazapineantidepressantModerate

    The risk is increased with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, tryptophan, buspirone, amphetamines, and St. (Mirtazapine label, Warnings and precautions)

  • ModafinilCNS stimulantModerate

    Risk of Abuse and Dependence Phentermine is related chemically and pharmacologically to amphetamine (d- and d l l-amphetamine) and other related stimulant drugs that have been extensively abused. (Phentermine label, Warnings and precautions)

  • Naltrexone and bupropionopioid antagonistModerate

    …tumor or infection, or metabolic disorders (e.g., hypoglycemia, hyponatremia, severe hepatic impairment, and hypoxia) excessive use of alcohol or sedatives, addiction to cocaine or stimulants, or withdrawal from sedatives patients with diabetes treated with insulin and/or oral diabetic medications (sulfonylureas and meglitinides) that may cause hypoglycemia concomitant… (Naltrexone and bupropion label, Warnings and precautions)

  • Nortriptylinetricyclic antidepressantModerate

    Close supervision and careful adjustment of the dosage are required when Pamelor is used with other anticholinergic drugs and sympathomimetic drugs. (Nortriptyline label, Drug interactions)

  • ParoxetineSSRIModerate

    The risk is increased with concomitant use of other serotonergic agents (including triptans, tricyclic antidepressants, fentanyl, tramadol, meperidine, methadone, lithium, tryptophan, buspirone, amphetamines, and St. (Paroxetine label, Warnings and precautions)

  • PioglitazonethiazolidinedioneModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • Pioglitazone and metforminthiazolidinedioneModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • Propranololbeta blockerModerate

    Pharmacodynamic Drug-Drug Interactions Adrenergic Agonists: Beta-blockers may antagonize the antihypertensive effects of clonidine, and rebound hypertension may result if clonidine is withdrawn abruptly. (Propranolol label, Drug interactions)

  • RepaglinidemeglitinideModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • RitonavirantiretroviralModerate

    Anesthetic: meperidine ↓ meperidine/ ↑ normeperidine (metabolite) Dosage increase and long-term use of meperidine with ritonavir are not recommended due to the increased concentrations of the metabolite normeperidine which has both analgesic activity and CNS stimulant activity (e.g., seizures). (Ritonavir label, Drug interactions)

  • SemaglutideGLP-1 receptor agonistModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • SertralineSSRIModerate

    The risk is increased with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, meperidine, methadone, tryptophan, buspirone, amphetamines, and St. (Sertraline label, Warnings and precautions)

  • SitagliptinDPP-4 inhibitorModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • Sitagliptin and metforminDPP-4 inhibitorModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • SolriamfetolCNS stimulantModerate

    Risk of Abuse and Dependence Phentermine is related chemically and pharmacologically to amphetamine (d- and d l l-amphetamine) and other related stimulant drugs that have been extensively abused. (Phentermine label, Warnings and precautions)

  • Sotalolbeta blockerModerate

    Beta-2-Receptor Stimulants Beta-agonists such as albuterol, terbutaline and isoproterenol may have to be administered in increased dosages when used concomitantly with sotalol. (Sotalol label, Drug interactions)

  • Circulatory Shock Circulatory shock with fever, severe hypotension, and confusion requiring intravenous fluid resuscitation and vasopressors has occurred within minutes to hours of re-challenge with trimethoprim-sulfamethoxazole products in patients with history of recent (days to weeks) exposure to sulfamethoxazole and trimethoprim. (Sulfamethoxazole and trimethoprim label, Warnings)

  • TemazepambenzodiazepineModerate

    Prescribe the lowest effective dosage; avoid or minimize concomitant use of CNS depressants and other substances associated with abuse, misuse, and addiction (e.g., opioid analgesics, stimulants); and advise patients on the proper disposal of unused drug. (Temazepam label, Warnings)

  • Timololbeta blockerModerate

    If necessary during surgery, the effects of beta-adrenergic blocking agents may be reversed by sufficient doses of adrenergic agonists. (Timolol 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)

  • TirzepatideGLP-1 receptor agonistModerate

    • A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (Phentermine label, Warnings and precautions)

  • TriazolambenzodiazepineModerate

    Prescribe the lowest effective dosage; avoid or minimize concomitant use of CNS depressants and other substances associated with abuse, misuse, and addiction (e.g., opioid analgesics, stimulants); and advise patients on the proper disposal of unused drug. (Triazolam label, Warnings and precautions)

  • VenlafaxineSNRIModerate

    The risk is increased with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, tryptophan, meperidine, methadone, busipirone, amphetamines, and St. (Venlafaxine label, Warnings and precautions)

  • VilazodoneSSRIModerate

    The risk is increased with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, meperidine, methadone, lithium, tramadol, tryptophan, buspirone, amphetamines, and St. (Vilazodone label, Warnings and precautions)

  • VortioxetineantidepressantModerate

    The risk is increased with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, tryptophan, meperidine, methadone, buspirone, amphetamines, and St. (Vortioxetine label, Warnings and precautions)

  • ZiprasidoneantipsychoticModerate

    The risk is increased with concomitant use of other serotonergic drugs (including selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), triptans, tricyclic antidepressants, fentanyl, tramadol, meperidine, methadone, lithium, tryptophan, buspirone, amphetamines, and St. (Ziprasidone label, Warnings and precautions)

Minor mentions (25)

  • Severe reactions have required intervention with vasopressor agents and supportive measures. (Benzonatate label, Warnings)

  • Buspironeserotonergic drugMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

  • Cyclobenzaprinemuscle relaxantMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

  • Dextromethorphanserotonergic drugMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

  • Dihydroergotamineergot alkaloidMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

  • Doxepintricyclic antidepressantMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

  • EletriptantriptanMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

  • FlibanserinCNS depressantMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

  • GranisetronQT-prolonging drugMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine 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)

  • Labetalolbeta blockerMinor

    Labetalol has also been reported to produce a false-positive test for amphetamine when screening urine for the presence of drugs using the commercially available assay methods. (Labetalol label, Drug interactions)

  • Lithiumserotonergic drugMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

  • MeperidineopioidMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

  • OndansetronQT-prolonging drugMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

  • PropofolCNS depressantMinor

    These effects are responsive to discontinuation of DIPRIVAN, intravenous fluid administration, and/or vasopressor therapy. (Propofol label, Warnings and precautions)

  • Prucaloprideserotonergic drugMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

  • Ramelteonsedative-hypnoticMinor

    In addition, in vitro data indicate that ramelteon does not cause false-positive results for benzodiazepines, opiates, barbiturates, cocaine, cannabinoids, or amphetamines in two standard urine drug screening methods in vitro . (Ramelteon label, Warnings and precautions)

  • RizatriptantriptanMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

  • SumatriptantriptanMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

  • Sumatriptan and naproxentriptanMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

  • TapentadolopioidMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

  • TiagabineanticonvulsantMinor

    In most cases, patients were using concomitant medications (antidepressants, antipsychotics, stimulants, narcotics) that are thought to lower the seizure threshold. (Tiagabine label, Warnings)

  • TramadolopioidMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

  • TrazodoneantidepressantMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

  • ZolmitriptantriptanMinor

    The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. (Phentermine label, Warnings and precautions)

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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.