Atazanavir and Nirmatrelvir and ritonavir interaction
Atazanavir 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 Atazanavir (REYATAZ) label · effective 2024-12-05
…contraindicated with, but not limited to, the following drugs listed in Table 6: Table 6: Drugs Contraindicated with REYATAZ (Information in the table applies to REYATAZ with or without ritonavir, unless otherwise indicated) a See Drug Interactions, Table 16 (7) for parenterally administered midazolam. b See Drug Interactions, Table 16 (7) for sildenafil when dosed…
…within class that are contraindicated with REYATAZ Alpha 1-adrenoreceptor antagonist Alfuzosin Anticonvulsants Carbamazepine, phenobarbital, phenytoin Antiarrhythmics Amiodarone (with ritonavir), quinidine (with ritonavir) Antimycobacterials Rifampin Antineoplastics Apalutamide, encorafenib, irinotecan, ivosidenib Antipsychotics Lurasidone (with ritonavir), pimozide…
Use of REYATAZ without ritonavir is not recommended when coadministered with drugs highly dependent on CYP2C8 with narrow therapeutic indices (eg, paclitaxel, repaglinide).
Antiarrhythmics: amiodarone, quinidine amiodarone, bepridil, lidocaine (systemic), quinidine ↑ amiodarone, bepridil, lidocaine (systemic), quinidine Concomitant use of REYATAZ with ritonavir and either quinidine or amiodarone is contraindicated due to the potential for serious or life-threatening reactions such as cardiac arrhythmias [see Contraindications (4)…
Coadministration with REYATAZ without ritonavir has the potential to produce serious and/or life-threatening adverse events but has not been studied.
From the Nirmatrelvir and ritonavir (Paxlovid) label · effective 2026-02-19
• HIV-1 Drug Resistance: PAXLOVID use may lead to a risk of HIV-1 developing resistance to HIV protease inhibitors in individuals with uncontrolled or undiagnosed HIV-1 infection.
Risk of HIV-1 Resistance Development Because nirmatrelvir is co-administered with ritonavir, there may be a risk of HIV-1 developing resistance to HIV protease inhibitors in individuals with uncontrolled or undiagnosed HIV-1 infection [see Contraindications (4) and Drug Interactions (7) ] .
Monitor for increased PAXLOVID or protease inhibitor adverse events .
Anti-HIV protease inhibitors atazanavir, darunavir, tipranavir ↑ protease inhibitor For further information, refer to the respective protease inhibitors' prescribing information.
Anti-HIV efavirenz, maraviroc, nevirapine, zidovudine, bictegravir/ emtricitabine/ tenofovir ↑ efavirenz ↑ maraviroc ↑ nevirapine ↓ zidovudine ↑ bictegravir ↔ emtricitabine ↑ tenofovir For further information, refer to the respective anti-HIV drugs prescribing information.
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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.