Elvitegravir, cobicistat, emtricitabine, and tenofovir and Famciclovir interaction
Elvitegravir, cobicistat, emtricitabine, and tenofovir and Famciclovir: both prescribing labels mention this combination without an instruction to avoid it or change the dose.
Mentioned, no instruction to avoid. Worth knowing; rarely a reason to change anything on its own.
What the FDA labels say
From the Famciclovir label · effective 2026-01-14
An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes.
No clinically significant effect on the pharmacokinetics of zidovudine, its metabolite zidovudine glucuronide, or emtricitabine was observed following a single oral dose of 500 mg famciclovir coadministered with zidovudine or emtricitabine.
…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.
From the Elvitegravir, cobicistat, emtricitabine, and tenofovir (Genvoya) label · effective 2025-02-03
…GENVOYA Based on drug interaction studies conducted with the components of GENVOYA, no clinically significant drug interactions have been observed or are expected when GENVOYA is combined with the following drugs: famciclovir, famotidine, ledipasvir, methadone, omeprazole, prasugrel (active metabolite), sertraline, sofosbuvir, velpatasvir, and voxilaprevir.
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.