Drug interactions
Fosphenytoin + Vardenafil
Severity: Moderate
Fosphenytoin and Vardenafil: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Phenytoin, the active form of fosphenytoin, induces CYP3A4 and can lower vardenafil levels. This may lead to reduced efficacy.
What this interaction means in plain words
Fosphenytoin and Vardenafil can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Fosphenytoin belongs to Central Nervous System; Vardenafil belongs to Genitourinary.
Why it happens
CYP3A4 induction increases vardenafil metabolism.
What to do
Monitor response to vardenafil and consider a dose increase within labeled limits or an alternative treatment if ineffective.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Fosphenytoin and Vardenafil, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Vardenafil
- Amyl nitrite + Vardenafil Contraindicated
- Glyceryl trinitrate pr + Vardenafil Contraindicated
- Isosorbide dinitrate + Vardenafil Contraindicated
- Isosorbide mononitrate + Vardenafil Contraindicated
- Nicorandil + Vardenafil Contraindicated
- Nitroglycerin po + Vardenafil Contraindicated
Other interactions of Fosphenytoin
- Dronedarone + Fosphenytoin Contraindicated
- Fosphenytoin + Ledipasvir-sofosbuvir Contraindicated
- Fosphenytoin + Lorlatinib Contraindicated
- Fosphenytoin + Lurasidone Contraindicated
- Fosphenytoin + Ranolazine Contraindicated
- Fosphenytoin + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
Frequently asked questions
Can I take Fosphenytoin with Vardenafil?
MediHelp rates the interaction as moderate. Fosphenytoin and Vardenafil can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Phenytoin, the active form of fosphenytoin, induces CYP3A4 and can lower vardenafil levels. This may lead to reduced efficacy.
How serious is the interaction between Fosphenytoin and Vardenafil?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor response to vardenafil and consider a dose increase within labeled limits or an alternative treatment if ineffective.
What other medicines interact with Vardenafil?
MediHelp also lists interactions of Vardenafil with, for example, Amyl nitrite, Glyceryl trinitrate pr, Isosorbide dinitrate. The full list is on the Vardenafil page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
