Rifampin and Nevirapine: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Nevirapine
Rifampin
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 nevirapine exposure and reduced efficacy of nevirapine
Interaction Deep Dive
Do not coadminister nevirapine, a substrate of CYP3A4, with rifAMPin, a inducer of CYP3A4. Coadministered rifAMPin may cause reduced nevirapine exposure, possibly resulting in reduced nevirapine effectiveness. Consider using rifabutin as an alternative to rifAMPin12 or efavirenz as an alternative to nevirapine. However, if efavirenz cannot be used, nevirapine and rifAMPin may be used together with nevirapine initiated as a twice daily regimen (without the once daily lead-in phase). Monitoring of HIV RNA and therapeutic drug concentrations is recommended 3. In a randomized, comparative study in HIV-1 and TB-positive Thai adults receiving standard antiretroviral therapy and rifAMPin-based TB therapy, more patients receiving nevirapine (400 mg/day) had lower than minimum plasma concentrations compared with patients receiving efavirenz (600 mg/day) 4.
Why it happens (mechanism)
Induction of CYP3A4-mediated metabolism of nevirapine
Literature reports
2 reports — tap to read
a) In a randomized, comparative study in HIV-1 and TB-positive Thai adults (mean age, 37 years) receiving standard antiretroviral therapy (ART) and rifAMPin-based TB therapy, more patients receiving nevirapine (400 mg/day) had lower than minimum plasma concentrations compared with patients receiving efavirenz (600 mg/day); however, there was no overall difference in the primary efficacy endpoint of virologic suppression. All patients also received oral lamiVUDine and stavudine as part of the ART. The TB therapy consisted of rifAMPin 450 to 600 mg/day along with isoniazid, ethambutol, and pyrazinamide. The mean serum concentration levels at 12 hours (C12) for efavirenz at weeks 6 and 12 were 4.27 +/- 4.49 mg/L and 3.54 +/- 3.78 mg/L, respectively. For nevirapine, the mean C12 at weeks 6 and 12 were 5.59 +/- 3.48 mg/L and 5.6 +/- 2.65 mg/L, respectively. At week 12, 3.1% of subjects in the efavirenz group and 21.3% of subjects in the nevirapine group had a C12 level less than the recommended concentration (odds ratio, 8.396; 95% confidence interval (CI) 1.808 to 38.993; p=0.002). In an intent-to-treat analysis, 73.2% in the efavirenz group and 71.8% in the nevirapine group achieved HIV-1 RNA levels of less than 50 copies/mL at week 48, with a CD4 count of 274 cells/mm(3) and 252 cells/mm(3) (p greater than 0.05). Those with low C12 levels and a body weight of less than 55 kg were 3.6 and 2.4 times more likely, respectively, to develop all-cause treatment failure (p less than 0.05) 4.
b) Administration of rifAMPin had a clinically significant effect on nevirapine pharmacokinetics, decreasing area under the concentration-time curve (AUC) and maximum plasma concentration (Cmax) by greater than 50% (37% to 58% and 68%, respectively). Fourteen HIV-1-positive patients were administered rifAMPin 600 mg daily and nevirapine 200 mg daily for 14 days followed by 200 mg twice daily for 14 days. RifAMPin AUC increased 11% with no change in Cmax 12.
Common questions
Can I take Rifampin and Nevirapine together?
Reduced nevirapine exposure and reduced efficacy of nevirapine Always confirm with your pharmacist or prescriber before making any change.
How serious is the Rifampin and Nevirapine 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 "established". Well documented — supported by controlled studies or strong clinical data.
Questions for your pharmacist
- Does my dose of Rifampin or Nevirapine 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 (4)
- 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
- Centers for Disease Control and Prevention (CDC): Managing drug interactions in the treatment of HIV-related tuberculosis. Centers for Disease Control and Prevention (CDC). Atlanta, GA. 2014.
- Manosuthi W, Sungkanuparph S, Tantanathip P, et al: A randomized trial comparing plasma drug concentrations and efficacies between 2 nonnucleoside reverse-transcriptase inhibitor-based regimens in HIV-infected patients receiving rifampicin: the N2R Study. Clin Infect Dis 2009; 48(12):1752-1759.
Keep reading about Nevirapine
Keep reading about Rifampin
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