Meperidine and Nevirapine: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Nevirapine
Meperidine
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 meperidine exposure and reduced efficacy of meperidine
Interaction Deep Dive
Concomitant use of meperidine with CYP3A4/CYP2B6 inducers may reduce the exposure of meperidine, reducing efficacy and may lead to opioid withdrawal symptoms in patients physically dependent on meperidine. In a drug interaction study, the hepatic metabolism of meperidine may be enhanced by phenytoin (CYP3A4 inducer). Concomitant administration resulted in reduced half-life and bioavailability with increased clearance of meperidine in healthy subjects; however, blood concentrations of normeperidine were increased. If concomitant use is needed, closely monitor patients for decreased efficacy or signs of opioid withdrawal syndrome, and consider increasing the dose of meperidine as necessary. If a CYP3A4/CYP2B6 inducer is being discontinued, consider meperidine dose reduction and closely monitor patients for signs of respiratory depression or sedation12.
Why it happens (mechanism)
Induction of CYP3A4-mediated metabolism of meperidine; induction of CYP2B6-mediated metabolism of meperidine
Literature reports
1 report — tap to read
a) In a drug interaction study, the hepatic metabolism of meperidine may be enhanced by phenytoin (CYP3A4 inducer). Concomitant administration resulted in reduced half-life and bioavailability with increased clearance of meperidine in healthy subjects; however, blood concentrations of normeperidine were increased 12.
Common questions
Can I take Meperidine and Nevirapine together?
Reduced meperidine exposure and reduced efficacy of meperidine Always confirm with your pharmacist or prescriber before making any change.
How serious is the Meperidine 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 "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Meperidine 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 (2)
- Product Information: MEPERGAN intramuscular, intravenous injection, meperidine HCl, promethazine HCl intramuscular, intravenous injection. West-Ward Pharmaceuticals Corp (per FDA), Eatontown, NJ, 2023.
- Product Information: DEMEROL(R) oral tablets, oral solution, meperidine HCl oral tablets, oral solution. Validus Pharmaceuticals LLC (per FDA), Parsippany, NJ, 2023. DailyMed
Keep reading about Nevirapine
Keep reading about Meperidine
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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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