Isoniazid and Mefloquine interaction
Isoniazid and Mefloquine: the Mefloquine prescribing label describes an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Mefloquine (Mefloquine Hydrochloride) label · effective 2025-04-03
Ketoconazole (Potent Inhibitor of CYP3A4) Coadministration of a single 500 mg oral dose of mefloquine with 400 mg of ketoconazole once daily for 10 days in 8 healthy volunteers resulted in an increase in the mean C max and AUC of mefloquine by 64% and 79%, respectively, and an increase in the mean elimination half-life of mefloquine from 322 hours to 448 hours.
However, mefloquine is metabolized by CYP3A4 and inhibitors of CYP3A4 may modify the pharmacokinetics/metabolism of mefloquine, leading to an increase in mefloquine plasma concentrations and potential risk of adverse reactions.
Therefore, mefloquine hydrochloride tablets should be used with caution when administered concomitantly with CYP3A4 inhibitors.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
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.