Fosamprenavir and Nevirapine interaction
Fosamprenavir and Nevirapine: 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 Nevirapine label · effective 2026-07-15
Fosamprenavir ↓ Amprenavir ↑ Nevirapine Co-administration of nevirapine and fosamprenavir without ritonavir is not recommended.
Female gender and higher CD4 + cell counts at initiation of therapy place patients at increased risk; women with CD4 + cell counts greater than 250 cells/mm 3 , including pregnant women receiving nevirapine in combination with other antiretrovirals for the treatment of HIV-1 infection, are at the greatest risk.
Fosamprenavir/Ritonavir ↓ Amprenavir ↑ Nevirapine No dosing adjustments are required when nevirapine is co-administered with 700/100 mg of fosamprenavir/ritonavir twice daily.
The combination of nevirapine administered with fosamprenavir/ritonavir once daily has not been studied.
Drug Name Effect on Concentration of Nevirapine or Concomitant Drug Clinical Comment HIV Antiviral Agents: Protease Inhibitors (PIs) Atazanavir/Ritonavir The interaction between nevirapine and the drug was evaluated in a clinical study.
From the Fosamprenavir (Fosamprenavir Calcium) label · effective 2026-06-30
Non-nucleoside reverse transcriptase inhibitor: Nevirapine a Fosamprenavir calcium: ↓ Amprenavir ↑ Nevirapine Coadministration of nevirapine and fosamprenavir calcium without ritonavir is not recommended.
Initiation of medications that inhibit or induce CYP3A may increase or decrease concentrations of fosamprenavir calcium/ritonavir, respectively.
Coadministration of fosamprenavir calcium with drugs that induce CYP3A4 may decrease amprenavir (active metabolite) concentrations leading to potential loss of virologic activity.
Coadministration of fosamprenavir calcium and drugs that induce CYP3A4, such as rifampin, may decrease amprenavir concentrations and reduce its therapeutic effect.
The combination of nevirapine administered with fosamprenavir calcium/ritonavir once-daily regimen has not been studied.
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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.