Rifampin and Voriconazole interaction
Rifampin and Voriconazole: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Rifampin (Rifadin IV) label · effective 2026-05-27
…Anticoagulants Prevention or Management: Perform prothrombin time daily or as frequently as necessary to establish and maintain the required dose of anticoagulant Warfarin Decrease exposure Antifungals Fluconazole Decrease AUC by 23% Itraconazole Prevention or Management: Not recommended 2 weeks before and during itraconazole treatment Decrease exposure Ketoconazole Decrease…
From the Voriconazole label · effective 2026-06-02
• Long-acting barbiturates • Rifabutin • Rifampin • Ritonavir Concomitant use with high-dose ritonavir (400 mg every 12 hours) is contraindicated.
…(12.3)] Drug/Drug Class (Mechanism of Interaction by the Drug) Voriconazole Plasma Exposure (C max and AUC τ after 200 mg every 12 hours) Prevention or Management Recommendations Rifampin Results based on in vivo clinical studies generally following repeat oral dosing with 200 mg every 12 hours voriconazole to healthy subjects and Rifabutin (CYP450 Induction)…
Concomitant use of voriconazole is contraindicated with drugs and herbal products that induce CYP2C19, CYP2C9, and/or CYP3A4 and for which significantly reduced voriconazole plasma concentrations may be associated with loss of efficacy [see Drug Interactions (7) ]: • Carbamazepine • Efavirenz Concomitant use with efavirenz dosages of 400 mg every 24 hours or…
• Concomitant use with drugs and herbal products that induce CYP2C19, CYP2C9, and/or CYP3A4 and for which significantly reduced voriconazole plasma concentrations may be associated with loss of efficacy ( 4 , 7 )
John's Wort (CYP450 inducer; P-gp inducer) Significantly Reduced Contraindicated Oral Contraceptives containing ethinyl estradiol and norethindrone (CYP2C19 Inhibition) Increased Monitoring for adverse reactions and toxicity related to voriconazole is recommended for concomitant administration with oral contraceptives.
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.