Mexiletine/Phenytoin 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:
Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
Phenytoin may speed up how quickly your body processes your mexiletine.
What might happen:
The blood level of your mexiletine may decrease and it may not work as well.
What you should do about this interaction:
Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together. You doctor may want to monitor you more closely while you are these medications to make sure your mexiletine is still working for you. The dose of your mexiletine may need to be adjusted after you start or stop phenytoin.If you experience a fast or irregular heartbeat, or feel like you might faint, contact your doctor.Your healthcare professionals (e.g. doctor or pharmacist) may already be aware of this drug 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.Mexiletine US Prescribing Information. Teva Pharmaceuticals USA, Inc. October, 2018.
- 2.Pentikainen PJ, Koivula IH, Hiltunen HA. Effect of rifampicin treatment on the kinetics of mexiletine. Eur J Clin Pharmacol 1982;23(3):261-6.
- 3.Begg EJ, Chinwah PM, Webb C, Day RO, Wade DN. Enhanced metabolism of mexiletine after phenytoin administration. Br J Clin Pharmacol 1982; 14:219-223.
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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.