Acorda Therapeutics and the FDA have informed healthcare professionals of changes to the CONTRAINDICATIONS and WARNINGS Sections of the product labeling for Zanaflex (tizanidine), a medication used for a variety of purposes by patients with Migraine disease and other head pain disorders.
Zanaflex is described by the FDA as "a drug used to treat spacticity." We see it prescribed for Migraine, headache, and pain patients for muscle spasms, treating some sleep disorders such as periodic limb movement disorder, to improve the quality of sleep, and as a headache and Migraine preventive.
In pharmacokinetic studies where tizanidine was coadministered with either fluvoxamine (the antidepressant Luvox) or ciprofloxacin (the antibiotic Cipro) (CYP1A2 inhibitors), the serum concentration of tizanidine was significantly increased and potentiated its hypotensive and sedative effects. Although there are no clinical studies evaluating the effects of other CYP1A2 inhibitors on tizanidine, coadministration of tizanidine with other CYP1A2 inhibitors [zileuton (for asthma), other fluroquinolones, antiarrythmics, cimetidine (Tagamet), famotidine (pepcid), oral contraceptives, acyclovir (Zovirax) and ticlopidine (Ticlid)] should be avoided. If their use is clinically necessary, they should be used with caution.
If you're taking Zanaflex (tizanidine) with any of the medications listed in the MedWatch warning, you may wish to consult your doctor about this issue. Do not discontinue your medications without consulting your physician.
MedWatch Safety Information. "Zanaflex (tizanidine hydrochloride) Tablets and Capsules." April 11, 2007.
Healthcare Professional Letter. Acorda Therapeutics and the FDA. "Updated Safety Informaiton: Contraindications to the use of Tizanidine." March 5, 2007.