Dofetilide and Nirmatrelvir and ritonavir interaction
Dofetilide 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
…concentrations are associated with serious and/or life-threatening reactions [see Drug Interactions (7.3) ] : • Alpha 1-adrenoreceptor antagonist: alfuzosin • Antianginal: ranolazine • Antiarrhythmic: amiodarone, dronedarone, flecainide, propafenone, quinidine • Anti-gout: colchicine (in patients with renal and/or hepatic impairment [see Table 2 , Drug Interactions…
Antiarrhythmics amiodarone, dronedarone, flecainide, propafenone, quinidine ↑ antiarrhythmic Co-administration contraindicated due to potential for cardiac arrhythmias [see Contraindications (4) ] .
Antiarrhythmics lidocaine (systemic), disopyramide ↑ antiarrhythmic Caution is warranted and therapeutic concentration monitoring is recommended for antiarrhythmics if available.
From the Dofetilide label · effective 2026-04-24
…grouped as ACE inhibitors, oral anticoagulants, calcium channel blockers, beta blockers, cardiac glycosides, inducers of CYP3A4, substrates and inhibitors of CYP3A4, substrates and inhibitors of P-glycoprotein, nitrates, sulphonylureas, loop diuretics, potassium sparing diuretics, thiazide diuretics, substrates and inhibitors of tubular organic cation transport,…
Dofetilide is not an inhibitor of CYP3A4 nor of other cytochrome P450 isoenzymes (e.g., CYP2C9, CYP2D6) and is not expected to increase levels of drugs metabolized by CYP3A4.
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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.