Tizanidine/Estrogen-Containing Hormonal Contraceptives 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.
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:
Hormonal contraceptives may slow down how quickly your liver processes tizanidine.
What might happen:
The amount of tizanidine in your blood may increase and cause more side effects than normal, including severe low blood pressure, drowsiness, decreased ability to move your body, and irregular heart beat. The effects on your heart may be life-threatening.
What you should do about this interaction:
Let your healthcare professional (e.g. doctor or pharmacist) know right away that you are using these medicines together. Let your doctor know right away if you notice any irregular heartbeat or have any dizziness or fainting episodes. Your doctor may want to perform an electrocardiogram (ECG) on you to check your heart rate and rhythm. Use caution when performing tasks that require alertness.Your doctor may want to change the dose of your tizanidine.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.Zanaflex (tizanidine hydrochloride) US prescribing information. Acordia Therapeutics, Inc. November 7, 2013.
- 2.Drew BJ, Ackerman MJ, Funk M, Gibler WB, Kligfield P, Menon V, Philippides GJ, Roden DM, Zareba W. Prevention of torsade de pointes in hospital settings: a scientific statement from the American Heart Association and the American College of Cardiology Foundation. J Am Coll Cardiol 2010 Mar 2;55(9):934-47.
- 3.Granfors MT, Backman JT, Laitila J, Neuvonen PJ. Oral contraceptives containing ethinyl estradiol and gestodene markedly increase plasma concentrations and effects of tizanidine by inhibiting cytochrome P450 1A2. Clin Pharmacol Ther 2005 Oct;78(4):400-11.
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.