Hydantoins/Omeprazole; Esomeprazole Interactions

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Serious. These medicines may interact and cause very harmful effects. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

When these two medicines are taken together, your body may not process your seizure medicine or your proton pump inhibitor properly.

What might happen:

The blood levels of your seizure medicine may increase and cause more side effects than expected. The blood levels of your proton pump inhibitor may decrease and it may not work as well.

What you should do about this interaction:

If you experience nausea, vomiting, confusion, dizziness, or other symptoms, contact your doctor. It may be necessary to check your blood levels more often or to change the dose of your medicine.Contact your healthcare provider if your proton pump inhibitor does not seem to be working as well for your stomach condition.Your healthcare professionals (e.g. doctor or pharmacist) may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.

  • 1.Dilantin (phenytoin sodium) US prescribing information. Pfizer, Inc. March, 2022.
  • 2.Prilosec (omeprazole) US prescribing information. AstraZeneca Pharmaceuticals LP June, 2018.
  • 3.Nexium (esomeprazole magnesium) US prescribing information. AstraZeneca Pharmaceuticals LP August, 2021.
  • 4.Prichard PJ, Walt RP, Kitchingman GK, Somerville KW, Langman MJ, Williams J, Richens A. Oral phenytoin pharmacokinetics during omeprazole therapy. Br J Clin Pharmacol 1987 Oct;24(4):543-5.
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  • 8.This information is based on an extract from the Certara Drug Interaction Database (DIDB) Platform, Copyright Certara 1999-2023..
  • 9.Bosilkovska M, Samer CF, Deglon J, Rebsamen M, Staub C, Dayer P, Walder B, Desmeules JA, Daali Y. Geneva cocktail for cytochrome p450 and P-glycoprotein activity assessment using dried blood spots. Clin Pharmacol Ther 2014 Sep;96(3):349-59.

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CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.