Morphine and Nirmatrelvir and ritonavir interaction
Morphine 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 Nirmatrelvir and ritonavir (Paxlovid) label · effective 2026-02-19
…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) ] .
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.
From the Morphine (Morphine Sulfate) label · effective 2026-02-03
P-Glycoprotein (P-gp) Inhibitors Clinical Impact: The concomitant use of P-gp inhibitors can increase the exposure to morphine by two-fold and can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death.
Intervention: Evaluate patients for signs of respiratory depression that may be greater than otherwise expected and decrease the dosage of Morphine Sulfate Oral Solution and/or the P-gp inhibitor as necessary.
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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.