Meperidine and Nirmatrelvir and ritonavir interaction
Meperidine and Nirmatrelvir and ritonavir: 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 Meperidine (DEMEROL) label · effective 2026-07-20
Cytochrome P450 3A4 Interaction The concomitant use of DEMEROL Injection with all cytochrome P450 3A4 inhibitors may result in an increase in meperidine plasma concentrations, which could increase or prolong adverse reactions and may cause potentially fatal respiratory depression.
Monitor patients receiving DEMEROL Injection and any CYP3A4 inhibitor or inducer [see Warnings and Precautions (5.5) , Drug Interactions (7) ] .
• Concomitant use with CYP3A4 inhibitors (or discontinuation of CYP3A4 inducers) can result in a fatal overdose of meperidine.
Examples: Macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconizole), protease inhibitors (e.g., ritonavir) CYP3A4 and CYP2B6 Inducers Clinical Impact: The concomitant use of DEMEROL Injection and CYP3A4 inducers or CYP2B6 inducers can decrease the plasma concentration of meperidine [see Clinical Pharmacology (12.3) ] , resulting…
Risks of Concomitant Use or Discontinuation of Cytochrome P450 3A4 Inhibitors and Inducers Concomitant use of DEMEROL Injection with a CYP3A4 inhibitor, such as macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), and protease inhibitors (e.g., ritonavir), may increase plasma concentrations of meperidine and prolong opioid…
From the Nirmatrelvir and ritonavir (Paxlovid) label · effective 2026-02-19
Narcotic analgesics fentanyl, hydrocodone, oxycodone, meperidine ↑ fentanyl ↑ hydrocodone ↑ oxycodone ↑ meperidine Careful monitoring of therapeutic and adverse effects (including potentially fatal respiratory depression) is recommended when fentanyl, hydrocodone, oxycodone, or meperidine is concomitantly administered with PAXLOVID.
…voclosporin • Microsomal triglyceride transfer protein inhibitor: lomitapide • Migraine medications: eletriptan, ubrogepant • Mineralocorticoid receptor antagonists: finerenone • Non-opioid analgesic (selective blocker of Na v 1.8 sodium channels): suzetrigine • Opioid antagonists: naloxegol • PDE5 inhibitor: sildenafil (Revatio ® ) when used for pulmonary arterial…
Opioid antagonists naloxegol ↑ naloxegol Co-administration contraindicated due to the potential for opioid withdrawal symptoms [see Contraindications (4) ] .
Sedative/hypnotics triazolam, oral midazolam ↑ triazolam ↑ midazolam Co-administration contraindicated due to potential for extreme sedation and respiratory depression [see Contraindications (4) ] .
Serotonin receptor 1A agonist/ serotonin receptor 2A antagonist flibanserin ↑ flibanserin Co-administration contraindicated due to potential for hypotension, syncope, and CNS depression [see Contraindications (4) ] .
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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.