Atazanavir and Avanafil interaction
Atazanavir and Avanafil: 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 Avanafil label · effective 2025-12-17
Do not use avanafil in patients taking strong CYP3A4 inhibitors [see Warnings and Precautions ( 5.2 ) and Dosage and Administration ( 2.3 )].
Inhibitors of CYP3A4 may reduce avanafil clearance and increase plasma concentrations of avanafil.
For patients taking concomitant moderate CYP3A4 inhibitors (including erythromycin, amprenavir, aprepitant, diltiazem, fluconazole, fosamprenavir, and verapamil), the maximum recommended dose of avanafil is 50 mg, not to exceed once every 24 hours [see Drug Interactions ( 7.2 )].
• CYP3A4 inhibitors (e.g., ketoconazole, ritonavir, erythromycin) increase avanafil exposure ( 7.2 )
Studies have shown that drugs that inhibit CYP3A4 can increase avanafil exposure.
From the Atazanavir (REYATAZ) label · effective 2024-12-05
John’s wort ( Hypericum perforatum ) Lipid-Modifying Agents: Lomitapide, lovastatin, simvastatin Phosphodiesterase-5 (PDE-5) Inhibitor Sildenafil b when dosed as REVATIO ® for the treatment of pulmonary arterial hypertension Protease Inhibitors Indinavir Non-nucleoside Reverse Transcriptase Inhibitors Nevirapine • In patients with previously demonstrated hypersensitivity…
PDE5 inhibitors: sildenafil, tadalafil, vardenafil ↑ sildenafil ↑ tadalafil ↑ vardenafil Coadministration with REYATAZ has not been studied but may result in an increase in PDE5 inhibitor-associated adverse reactions, including hypotension, syncope, visual disturbances, and priapism.
Use of PDE5 inhibitors for erectile dysfunction: Use VIAGRA ® (sildenafil) with caution at reduced doses of 25 mg every 48 hours with increased monitoring for adverse events.
Use of PDE5 inhibitors for pulmonary arterial hypertension (PAH): Coadministration of REYATAZ with REVATIO ® (sildenafil) for the treatment of pulmonary hypertension (PAH) is contraindicated [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.