Drug interactions
Meperidine + Nirmatrelvir
Severity: Major
Meperidine and Nirmatrelvir: major interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Nirmatrelvir is given with ritonavir, which strongly inhibits CYP3A4 and may raise meperidine exposure. Ritonavir may also reduce formation of the neurotoxic metabolite normeperidine through effects on enzymes, but overall opioid toxicity risk remains. The labeling of the combination product lists meperidine-type interactions as ones to avoid.
What this interaction means in plain words
Meperidine and Nirmatrelvir can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Meperidine belongs to Musculoskeletal; Nirmatrelvir belongs to Anti Virals.
Why it happens
Ritonavir boosting inhibits CYP3A4, which metabolises meperidine.
What to do
Use a non-interacting analgesic during the 5-day course where possible. If meperidine is essential, use the lowest dose and monitor for sedation and respiratory depression.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Meperidine
- Alvimopan + Meperidine Contraindicated
- Isocarboxazid + Meperidine Contraindicated
- Meperidine + Methylene blue Contraindicated
- Meperidine + Olanzapine / samidorphan Contraindicated
- Meperidine + Phenelzine Contraindicated
- Meperidine + Procarbazine Contraindicated
Other interactions of Nirmatrelvir
- Alfuzosin + Nirmatrelvir Contraindicated
- Amiodarone + Nirmatrelvir Contraindicated
- Apalutamide + Nirmatrelvir Contraindicated
- Carbamazepine + Nirmatrelvir Contraindicated
- Colchicine + Nirmatrelvir Contraindicated
- Dronedarone + Nirmatrelvir Contraindicated
Frequently asked questions
Can I take Meperidine with Nirmatrelvir?
MediHelp rates the interaction as major. Meperidine and Nirmatrelvir can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Nirmatrelvir is given with ritonavir, which strongly inhibits CYP3A4 and may raise meperidine exposure. Ritonavir may also reduce formation of the neurotoxic metabolite normeperidine through effects on enzymes, but overall opioid toxicity risk remains. The labeling of the combination product lists meperidine-type interactions as ones to avoid.
How serious is the interaction between Meperidine and Nirmatrelvir?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use a non-interacting analgesic during the 5-day course where possible. If meperidine is essential, use the lowest dose and monitor for sedation and respiratory depression.
What other medicines interact with Meperidine?
MediHelp also lists interactions of Meperidine with, for example, Alvimopan, Isocarboxazid, Methylene blue. The full list is on the Meperidine page.
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