Nevirapine and Nelfinavir: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Nevirapine
Nelfinavir
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Reduced nelfinavir exposure and reduced active metabolite (M8) exposure
Interaction Deep Dive
Concomitant use of nelfinavir (a CYP3A substrate) and nevirapine (a CYP3A inducer) decreased nelfinavir Cmin and exposure of the active metabolite (M8). In a study of patients with HIV-1 infection (n=23) administered nelfinavir 750 mg three times daily with nevirapine 200 mg daily for 14 days then twice daily for 14 days, no effect on nelfinavir AUC or Cmax was observed; however, Cmin decreased 32% (90% CI, 5% to 50%). Additionally, the AUC, Cmax, and Cmin of the active metabolite (M8) decreased 62% (90% CI, 53% to 70%), 59% (90% CI, 48% to 68%), and 66% (90% CI, 55% to 74%), respectively. Although optimal dosage adjustments regarding safety and efficacy for this combination have not been established21.
Why it happens (mechanism)
Induction of CYP3A-mediated metabolism of nelfinavir
Literature reports
1 report — tap to read
a) In a study of patients with HIV-1 infection (n=23) administered nelfinavir 750 mg three times daily with nevirapine 200 mg daily for 14 days then twice daily for 14 days, no effect on nelfinavir AUC or Cmax was observed; however, Cmin decreased 32% (90% CI, 5% to 50%). Additionally, the AUC, Cmax, and Cmin of the active metabolite (M8) decreased 62% (90% CI, 53% to 70%), 59% (90% CI, 48% to 68%), and 66% (90% CI, 55% to 74%), respectively. Although optimal dosage adjustments regarding safety and efficacy for this combination have not been established 21.
Common questions
Can I take Nevirapine and Nelfinavir together?
Reduced nelfinavir exposure and reduced active metabolite (M8) exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Nevirapine and Nelfinavir interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Nevirapine or Nelfinavir need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (2)
- Product Information: VIRAMUNE(R) oral suspension, nevirapine oral suspension. Boehringer Ingelheim Pharmaceuticals Inc (per FDA), Ridgefield, CT, 2024. DailyMed
- Product Information: VIRAMUNE XR(R) oral extended-release tablets, nevirapine oral extended-release tablets. Boehringer Ingelheim Pharmaceuticals Inc (per FDA), Ridgefield, CT, 2024. DailyMed
Keep reading about Nevirapine
Keep reading about Nelfinavir
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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