Hydantoins/Rifamycins 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 properly.
What might happen:
The blood levels of your seizure medicine may decrease and cause seizures.
What you should do about this interaction:
If you experience any seizures, contact your doctor. It may be necessary to measure your blood levels of your seizure medicine more often. Your doctor may need to adjust the dose.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.Anderson Gail D. Chapter 42: Pharmacokinetics and Drug Interactions. In: Wyllie's Treatment of Epilepsy: Principles and Practice, 5th Ed. 2011.
- 2.Kay L, Kampmann JP, Svendsen TL, Vergman B, Hansen JE, Skovsted L, Kristensen M. Influence of rifampicin and isoniazid on the kinetics of phenytoin. Br J Clin Pharmacol 1985 Oct;20(4):323-6.
- 3.Abajo FJ. Phenytoin interaction with rifampicin. BMJ 1988 Oct 22; 297(6655):1048.
- 4.Priftin (rifapentine) US prescribing information. Sanofi-Aventis U.S. LLC July, 2010.
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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.