Folic Acid and Phenytoin: Drug Interaction Guide

Quick answer: Folic Acid and Phenytoin have a minor interaction — typically manageable with awareness.

Interaction severity: Minor — typically manageable

How Folic Acid interacts with Phenytoin

Folic acid supplementation may increase phenytoin metabolism or reduce its concentrations in some patients, potentially reducing seizure control.

What you should do

Do not withhold indicated folic acid, but monitor seizure control and consider checking phenytoin concentrations after starting substantial supplementation.

Key facts

Severity

Minor — typically manageable

Mechanism

Folic acid supplementation may increase phenytoin metabolism or reduce its concentrations in some patients, potentially ...

Action

Do not withhold indicated folic acid, but monitor seizure control and consider checking phenytoin concentrations after s...

Important medical disclaimer: This page provides educational information about drug interactions for general reference. It is not a substitute for professional medical advice, diagnosis, or treatment. Always discuss your specific medications with a qualified healthcare provider before starting, stopping, or changing any treatment. About our editorial team.

Frequently asked questions

Can I take Folic Acid and Phenytoin together?

Usually yes, with awareness. Do not withhold indicated folic acid, but monitor seizure control and consider checking phenytoin concentrations after starting substantial supplementation.

What is the severity of this interaction?

The interaction between Folic Acid and Phenytoin is classified as Minor — typically manageable. Folic acid supplementation may increase phenytoin metabolism or reduce its concentrations in some patients, potentially reducing seizure control.

What should I do if I'm prescribed both?

Do not withhold indicated folic acid, but monitor seizure control and consider checking phenytoin concentrations after starting substantial supplementation. Always consult your prescribing clinician — do not stop or change medications without medical guidance.

Last reviewed: by iMedic Medical Editorial Team. Our editorial process.