Metronidazole interactions

Metronidazole (Flagyl), an antibiotic has 91 documented interactions across the FDA labels and fact sheets we index: 7 major, 76 moderate, 7 minor, and 1 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 (7)

  • AlcoholAlcoholMajor

    Patients who consume alcohol or products containing propylene glycol during and for at least three days after LIKMEZ therapy. (Metronidazole label, Contraindications)

  • BosentanCYP3A4 inducerMajor

    Co-administration of such combinations of a CYP2C9 inhibitor plus a strong or moderate CYP3A inhibitor with TRACLEER is not recommended. (Bosentan label, Drug interactions)

  • DisulfiramCYP2C9 inhibitorMajor

    Patients who have used disulfiram within the last two weeks. (Metronidazole label, Contraindications)

  • DronabinolcannabinoidMajor

    …reactions to dronabinol include lip swelling, hives, disseminated rash, oral lesions, skin burning, flushing, throat tightness [see Adverse Reactions ( 6.2 )] . with a history of a hypersensitivity reaction to alcohol. who are receiving, or have recently received, disulfiram- or metronidazole-containing products within 14 days [see Warning and Precautions ( 5.3 )] . (Dronabinol label, Contraindications)

  • Moderate dual CYP3A4 and CYP2C9 inhibitors (fluconazole, amiodarone) or use of combined CYP3A4 and CYP2C9 inhibitors may increase exposure to macitentan: avoid co-administration with OPSUMIT ( 7.3 , 12.3 ). (Macitentan label, Drug interactions)

  • Avoid concomitant use of mebendazole and metronidazole ( 5.3 ) (Mebendazole label, Warnings and precautions)

  • TinidazoleantibioticMajor

    WARNING: POTENTIAL RISK FOR CARCINOGENICITY WARNING: POTENTIAL RISK FOR CARCINOGENICITY Carcinogenicity has been seen in mice and rats treated chronically with metronidazole, another nitroimidazole agent [see Nonclinical Toxicology (13.1)]. (Tinidazole label, Boxed warning)

Moderate interactions (76)

  • Alfuzosinalpha blockerModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • AmiodaroneantiarrhythmicModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • Amitriptylinetricyclic antidepressantModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • ApixabananticoagulantModerate

    Warfarin and Other Oral Anticoagulants : LIKMEZ can potentiate the anticoagulant effect. (Metronidazole label, Drug interactions)

  • AsenapineantipsychoticModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • AvanafilPDE5 inhibitorModerate

    HIV Protease inhibitor — Ritonavir (600 mg twice daily), a strong CYP3A4 inhibitor, which also inhibits CYP2C9, increased avanafil 50 mg single-dose C max and AUC equal to approximately 2-fold and 13-fold, and prolonged the half-life of avanafil to approximately 9 hours in healthy volunteers. (Avanafil label, Drug interactions)

  • Azithromycinmacrolide antibioticModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • Carvedilolbeta blockerModerate

    Amiodarone Amiodarone and its metabolite desethyl amiodarone, inhibitors of CYP2C9, and P- glycoprotein increased concentrations of the S(-)-enantiomer of carvedilol by at least 2 fold [see Clinical Pharmacology (12.5) ]. (Carvedilol label, Drug interactions)

  • CelecoxibNSAIDModerate

    Co-administration of celecoxib with drugs that are known to inhibit CYP2C9 (e.g., fluconazole) may enhance the exposure and toxicity of celecoxib whereas co-administration with CYP2C9 inducers (e.g., rifampin) may lead to compromised efficacy of celecoxib. (Celecoxib label, Drug interactions)

  • ChloroquineantimalarialModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • ChlorpromazineantipsychoticModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • CimetidineH2 blockerModerate

    Inhibitors of CYP450 Liver Enzymes The simultaneous administration of LIKMEZ and drugs that decrease microsomal liver enzymes, such as cimetidine, may prolong the half-life and decrease plasma clearance of metronidazole. (Metronidazole label, Drug interactions)

  • CiprofloxacinfluoroquinoloneModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • CitalopramSSRIModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • Clarithromycinmacrolide antibioticModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • ClozapineantipsychoticModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • DabigatrananticoagulantModerate

    Warfarin and Other Oral Anticoagulants : LIKMEZ can potentiate the anticoagulant effect. (Metronidazole label, Drug interactions)

  • DeutetrabenazineVMAT2 inhibitorModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • DiclofenacNSAIDModerate

    Co-administration of diclofenac with CYP2C9 inhibitors (e.g., voriconazole) may enhance the exposure and toxicity of diclofenac whereas co-administration with CYP2C9 inducers (e.g. rifampin) may lead to compromised efficacy of diclofenac. (Diclofenac label, Drug interactions)

  • DofetilideantiarrhythmicModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • DronedaroneantiarrhythmicModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • EdoxabananticoagulantModerate

    Warfarin and Other Oral Anticoagulants : LIKMEZ can potentiate the anticoagulant effect. (Metronidazole label, Drug interactions)

  • Elexacaftor, tezacaftor, and ivacaftorModerate

    Effect of TRIKAFTA on Other Drugs CYP2C9 Substrates Ivacaftor may inhibit CYP2C9; therefore, monitoring of the international normalized ratio (INR) during concomitant use of TRIKAFTA with warfarin is recommended. (Elexacaftor, tezacaftor, and ivacaftor label, Drug interactions)

  • EnoxaparinanticoagulantModerate

    Warfarin and Other Oral Anticoagulants : LIKMEZ can potentiate the anticoagulant effect. (Metronidazole label, Drug interactions)

  • Erythromycinmacrolide antibioticModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • EscitalopramSSRIModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • FingolimodimmunosuppressantModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • FlecainideantiarrhythmicModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • Fluconazoleazole antifungalModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • FluoxetineSSRIModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • FondaparinuxanticoagulantModerate

    Warfarin and Other Oral Anticoagulants : LIKMEZ can potentiate the anticoagulant effect. (Metronidazole label, Drug interactions)

  • GranisetronQT-prolonging drugModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • HaloperidolantipsychoticModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • HeparinanticoagulantModerate

    Warfarin and Other Oral Anticoagulants : LIKMEZ can potentiate the anticoagulant effect. (Metronidazole label, Drug interactions)

  • HydroxychloroquineQT-prolonging drugModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • HydroxyzineantihistamineModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • IloperidoneantipsychoticModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • Ketoconazoleazole antifungalModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • LacosamideanticonvulsantModerate

    Strong CYP3A4 or CYP2C9 Inhibitors Patients with renal or hepatic impairment who are taking strong inhibitors of CYP3A4 and CYP2C9 may have a significant increase in exposure to VIMPAT. (Lacosamide label, Drug interactions)

  • LevofloxacinfluoroquinoloneModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • Lithiumserotonergic drugModerate

    Lithium: Increased lithium serum concentrations; measure serum lithium and serum creatinine concentrations during therapy. (Metronidazole label, Drug interactions)

  • LoperamideQT-prolonging drugModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • MeloxicamNSAIDModerate

    Thus concomitant usage of CYP2C9 inhibitors (such as amiodarone, fluconazole, and sulphaphenazole) may lead to abnormally high plasma levels of meloxicam due to reduced metabolic clearance [ see Use in Specific Populations ( 8.8 ); and Clinical Pharmacology ( 12.3 , 12.5 ) ]. (Meloxicam label, Drug interactions)

  • MethadoneopioidModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • MoxifloxacinfluoroquinoloneModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • OfloxacinfluoroquinoloneModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • OndansetronQT-prolonging drugModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • PaliperidoneantipsychoticModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • PhenobarbitalbarbiturateModerate

    Inducers of CYP450 Liver Enzymes The simultaneous administration of LIKMEZ and drugs that induce microsomal liver enzymes, such as phenytoin or phenobarbital, may accelerate the elimination of metronidazole, resulting in reduced plasma concentrations of metronidazole. (Metronidazole label, Drug interactions)

  • PhenytoinanticonvulsantModerate

    Inducers of CYP450 Liver Enzymes The simultaneous administration of LIKMEZ and drugs that induce microsomal liver enzymes, such as phenytoin or phenobarbital, may accelerate the elimination of metronidazole, resulting in reduced plasma concentrations of metronidazole. (Metronidazole label, Drug interactions)

  • PimavanserinantipsychoticModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • PitolisantQT-prolonging drugModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • Posaconazoleazole antifungalModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • PromethazineantihistamineModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • QuetiapineantipsychoticModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • Ramelteonsedative-hypnoticModerate

    Fluconazole (strong CYP2C9 inhibitor): Increases systemic exposure of ramelteon; administer with caution. (Ramelteon label, Drug interactions)

  • RanolazineQT-prolonging drugModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • RisperidoneantipsychoticModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • RivaroxabananticoagulantModerate

    Warfarin and Other Oral Anticoagulants : LIKMEZ can potentiate the anticoagulant effect. (Metronidazole label, Drug interactions)

  • RosuvastatinstatinModerate

    Rosuvastatin plasma levels can be significantly increased with concomitant administration of inhibitors of CYP2C9 and transporters. (Rosuvastatin label, Drug interactions)

  • SolifenacinanticholinergicModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • Sotalolbeta blockerModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • TacrolimusimmunosuppressantModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • Tamoxifenselective estrogen receptor modulatorModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • TetrabenazineVMAT2 inhibitorModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • TolterodineanticholinergicModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • Torsemideloop diureticModerate

    CYP2C9: Concomitant use with CYP2C9 inhibitors can decrease torsemide clearance. (Torsemide label, Drug interactions)

  • TramadolopioidModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • TrazodoneantidepressantModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • ValbenazineVMAT2 inhibitorModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • VardenafilPDE5 inhibitorModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • VenlafaxineSNRIModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • Voriconazoleazole antifungalModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

  • WarfarinanticoagulantModerate

    Warfarin and Other Oral Anticoagulants : LIKMEZ can potentiate the anticoagulant effect. (Metronidazole label, Drug interactions)

  • Zafirlukastleukotriene receptor antagonistModerate

    Zafirlukast exposure is likely to be increased by other moderate and strong CYP2C9 inhibitors. (Zafirlukast label, Precautions)

  • ZiprasidoneantipsychoticModerate

    Drugs that Prolong the QT Interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. (Metronidazole label, Drug interactions)

Minor mentions (7)

  • Clopidogrelantiplatelet agentMinor

    However, at high concentrations in vitro , clopidogrel inhibits CYP2C9. (Clopidogrel label, Drug interactions)

  • Clotrimazoleazole antifungalMinor

    Fungal Superinfections Known or previously unrecognized candidiasis may present more prominent symptoms during therapy with LIKMEZ and requires treatment with an antifungal agent. (Metronidazole label, Warnings and precautions)

  • Econazoleazole antifungalMinor

    Fungal Superinfections Known or previously unrecognized candidiasis may present more prominent symptoms during therapy with LIKMEZ and requires treatment with an antifungal agent. (Metronidazole label, Warnings and precautions)

  • InfliximabimmunosuppressantMinor

    Serum infliximab concentrations appeared to be unaffected by baseline use of medications for the treatment of CD including corticosteroids, antibiotics (metronidazole or ciprofloxacin) and aminosalicylates. (Infliximab label, Drug interactions)

  • Itraconazoleazole antifungalMinor

    Fungal Superinfections Known or previously unrecognized candidiasis may present more prominent symptoms during therapy with LIKMEZ and requires treatment with an antifungal agent. (Metronidazole label, Warnings and precautions)

  • Miconazoleazole antifungalMinor

    Fungal Superinfections Known or previously unrecognized candidiasis may present more prominent symptoms during therapy with LIKMEZ and requires treatment with an antifungal agent. (Metronidazole label, Warnings and precautions)

  • TerbinafineantifungalMinor

    Fluconazole is an inhibitor of CYP2C9 and CYP3A enzymes. (Terbinafine label, Drug interactions)

No significant interaction reported (1)

  • TheophyllinemethylxanthineNo interaction

    …clinically significant interaction with theophylline.* albuterol, systemic and inhaled mebendazole amoxicillin medroxyprogesterone ampicillin, with or without methylprednisolone sulbactam metronidazole atenolol metoprolol azithromycin nadolol caffeine, dietary ingestion nifedipine cefaclor nizatidine co-trimoxazole (trimethoprim and sulfamethoxazole) norfloxacin ofloxacin… (Theophylline label, Drug interactions)

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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.