Fesoterodine/Selected Anticonvulsants; Barbiturates 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:

Barbiturates, carbamazepine, phenobarbital, phenytoin and primidone may speed up how quickly your liver processes fesoterodine.

What might happen:

The amount of fesoterodine and the active metabolites in your blood may decrease and they may not work as well.

What you should do about this interaction:

If you notice that your fesoterodine is not working as well, contact your healthcare professional (e.g. doctor or pharmacist). Your doctor may want to increase the dose of your medicine while you are taking your anticonvulsants.Your healthcare professionals 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.Toviaz (fesoterodine) UK summary of product characteristics. Pfizer Limited February, 2011.
  • 2.Toviaz (fesoterodine fumarate) US prescribing information. Pfizer June, 2021.

Selected from data included with permission and copyrighted by First Databank, Inc. This copyrighted material has been downloaded from a licensed data provider and is not for distribution, except as may be authorized by the applicable terms of use.

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.