Does Avanafil Interact with Ritonavir?
Avanafil and Ritonavir have a contraindicated drug interaction according to U.S. FDA drug labeling data. 7 DRUG INTERACTIONS • Avanafil can potentiate the hypotensive effect of nitrates, alpha-blockers, antihypertensives, and alcohol ( 7.1 ) • CYP3A4 inhibitors (e.g., ketoconazole, ritonavir, erythromycin) increase avanafil exposure ( 7.2 ) 7.1 Potential for Pharmacodynamic Interactions with Avanafil Nitrates Administration of avanafil to patients who are using any form of organic nitrate, is contraindicated. Other potent inhibitors of CYP3A4 (e.g., itraconazole, clarithromycin, nefazadone, ritonavir, saquinavir, nelfinavir, indinavir, atanazavir and telithromycin) would be expected to have similar effects. HIV Protease inhibitor — Ritonavir (600 mg twice daily), a strong CYP3A4 inhibitor, which also inhibits CYP2C9, increased avanafil 50 mg single-dose C max and AUC equal to approximately 2-fold and 13-fold, and prolonged the half-life of avanafil to approximately 9 hours in healthy volunteers. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This information is based on official FDA drug labeling sourced from OpenFDA and the NIH National Library of Medicine.
- Severity
- Contraindicated
- Avanafil Class
- Phosphodiesterase 5 Inhibitor
- Ritonavir Class
- Cytochrome P450 3A Inhibitor
- Management
- Do not take together
- Data Source
- U.S. FDA via OpenFDA
What To Tell Your Doctor or Pharmacist
If you are taking Avanafil and your doctor is considering prescribing Ritonavir (or vice versa), make sure to:
- Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
- Ask whether the benefits of combining these medications outweigh the risks for your specific situation
- Ask what symptoms to watch for that would indicate the interaction is causing problems
- Ask about alternative medications that do not interact with your current regimen
- Ask how frequently you should be monitored while these are co-prescribed
- Never stop or change either medication without first consulting your healthcare provider