Medication·Interactions·Reviewed June 9, 2026
Sildenafil interactions.
Sildenafil has 3 documented interactions in the NutriStack database, including 1 flagged to avoid or as a serious conflict. The full interaction list is below. None of this is a substitute for your prescriber's advice.
Sildenafil at a glance.
A quick, data-grounded summary. The full tables are below.
Sildenafil has 3 documented interactions in the NutriStack database, including 1 flagged to avoid or as a serious conflict. The full interaction list is below. None of this is a substitute for your prescriber's advice.
Substances that interact with sildenafil.
Every supplement and medication in the NutriStack database with a documented interaction with this drug, highest-severity first. Open any pair for the mechanism and sources.
| Substance | Interaction | What happens |
|---|---|---|
| St. John's Wort | Conflict | St. John's Wort induces CYP3A4, the primary enzyme metabolizing sildenafil. This can reduce sildenafil effectiveness. |
| L-Arginine | Caution | L-arginine is a nitric oxide precursor, and sildenafil enhances NO/cGMP signaling by inhibiting PDE5. Combined use can cause additive vasodilation... details → |
| L-Citrulline | Synergy | L-Citrulline can increase L-arginine availability and nitric-oxide-dependent signaling, which is upstream of sildenafil's PDE5 effect. In a small... |
The full sildenafil profile.
Uses, typical dosing, side effects, and the cited evidence for this medication.
Common sildenafil questions.
Quick answers drawn from the tables above.
What interacts with Sildenafil?
In the NutriStack database, Sildenafil has 3 documented interactions. The most notable include St. John's Wort, L-Arginine, and L-Citrulline. Check any specific combination before taking it and confirm with your prescriber.
Which substances should I avoid with Sildenafil?
Sildenafil is flagged against 1 substance in the database, including St. John's Wort. These pairings carry a higher risk and should be reviewed with a clinician before combining.
Is it safe to take St. John's Wort with Sildenafil?
NutriStack classifies the St. John's Wort and Sildenafil pairing as conflict: St. John's Wort induces CYP3A4, the primary enzyme metabolizing sildenafil. This can reduce sildenafil effectiveness. Avoid SJW with sildenafil as it may reduce its effectiveness. Always confirm with your prescriber.
Check your whole stack
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