Does Phenytoin Interact With Tadalafil?

Although specific interactions have not been studied, other CYP3A4 inducers, such as carbamazepine, phenytoin, and phenobarbital, would likely decrease tadalafil exposure.

Severity: Minor

Severity basis: drug interactions section. Combining Phenytoin (Anticonvulsant) and Tadalafil (PDE5 inhibitor) is classified as a minor interaction.

What to Do

This is generally a minor interaction, but review it with your pharmacist to be sure it is safe for you.

From the FDA Label

Although specific interactions have not been studied, other CYP3A4 inducers, such as carbamazepine, phenytoin, and phenobarbital, would likely decrease tadalafil exposure.

Source: FDA structured product labeling (set_id 00cbc656-768d-4995-bb6d-a0d4b32a248c).

Phenytoin

Anticonvulsant

Brands: Dilantin

View Phenytoin safety profile

Tadalafil

PDE5 inhibitor

Brands: Cialis, Adcirca

View Tadalafil safety profile

Check these against your full medication list in our free Interaction Checker

This information is educational — not medical advice.

This page is provided for general educational purposes and summarizes publicly available data from sources such as the U.S. Food & Drug Administration. It is not a substitute for the judgment of a licensed clinician and should not be used to start, stop, or change any medication. It may be incomplete or out of date, and individual circumstances vary. Always talk with your prescriber or pharmacist about your specific medications and health conditions. If you think you may have a medical emergency, call 911.

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