Darunavir and Sildenafil Interaction
Drug interaction information between Darunavir and Sildenafil.
Darunavir and Sildenafil have a documented major interaction in FDA labeling.
FDA drug labeling documents a major-severity interaction between Darunavir and Sildenafil. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
Darunavir increases the amount of sildenafil in your system, which can cause very low blood pressure or fainting.
What To Do
Avoid using these drugs together, as the combination can lead to dangerous side effects like vision changes or fainting.
FDA Label Information
avanafil, sildenafil, tadalafil, vardenafil ↑ PDE-5 inhibitors (only the use of sildenafil at doses used for treatment of erectile dysfunction has been studied with darunavir/ritonavir) Co-administration with darunavir/ritonavir may result in an increase in PDE-5 inhibitor-associated adverse events, including hypotension, syncope, visual disturbances and priapism. Use of PDE-5 inhibitors for pulmonary arterial hypertension (PAH): Co-administration with sildenafil used for PAH is contraindicated due to potential for sildenafil associated adverse reactions (which include visual disturbances,...
Darunavir Also Interacts With
- Lovastatin major
- Lurasidone major
- Pimozide major
- Midazolam major
- Dronedarone major
Sildenafil Also Interacts With
- Ketoconazole major
- Erythromycin major
- Itraconazole major
- Hydralazine/Isosorbide Dinitrate major
- Nirmatrelvir/Ritonavir major
Frequently Asked Questions
Can I take Darunavir and Sildenafil together?
This is a major interaction. Avoid using these drugs together, as the combination can lead to dangerous side effects like vision changes or fainting.
How serious is the interaction between Darunavir and Sildenafil?
This interaction is classified as "major" severity by the FDA. Major interactions may be life-threatening or cause serious side effects.
Why do Darunavir and Sildenafil interact?
Darunavir increases the amount of sildenafil in your system, which can cause very low blood pressure or fainting.
Understanding the Darunavir and Sildenafil Interaction
FDA-approved prescribing information for these two drugs flags their combination as a major-severity interaction. Darunavir belongs to the HIV Protease Inhibitor class and Sildenafil belongs to the PDE5 Inhibitor class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Darunavir increases the amount of sildenafil in your system, which can cause very low blood pressure or fainting. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Darunavir has 101 total documented interactions on file in this dataset, and Sildenafil has 10. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: Avoid using these drugs together, as the combination can lead to dangerous side effects like vision changes or fainting. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Darunavir or Sildenafil based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.