In the U.S.—

• Antispastic

Tizanidine ( tye-ZAN-i-dine) is used to help relax certain muscles in your body. It relieves the spasms, cramping, and tightness of muscles caused by medical problems such as multiple sclerosis or certain injuries to the spine. Tizanidine does not cure these problems, but it may allow other treatment, such as physical therapy, to be more helpful in improving your condition.

Tizanidine acts on the central nervous system (CNS) to produce its muscle relaxant effects. Its actions on the CNS may also cause some of the medicine's side effects.

ZANAFLEX is available only with your doctor's prescription, in the following dosage form:

Oral
• Tablets (U.S.)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For tizanidine, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to tizanidine. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Tizanidine has not been studied in pregnant women. However, studies in animals have shown that tizanidine causes birth defects and other pregnancy problems. Before taking ZANAFLEX, make sure your doctor knows if you are pregnant or if you become pregnant.

Breast-feeding—Tizanidine may pass into the breast milk. However, ZANAFLEX has not been reported to cause problems in nursing babies.

Children—Studies on ZANAFLEX have been done only in adult patients, and there is no specific information comparing use of tizanidine in children with use in other age groups.

Older adults—Studies in older adults show that tizanidine stays in the body a little longer than it does in younger adults. Your doctor will consider this when deciding on your dose.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking tizanidine, it is especially important that your health care professional know if you are taking any of the following:

• Antihypertensives (high blood pressure medicine)—Severe low blood pressure may occur

• Oral contraceptives (birth control pills)—The chance of side effects may be increased

• Phenytoin—Tizanidine may increase the blood levels of phenytoin, which increases the chance of serious side effects

• Kidney disease or
• Liver disease—The chance of side effects may be increased; higher blood levels of tizanidine may result and a smaller dose may be needed

Take ZANAFLEX only as directed. Do not take more of it and do not take it more often than recommended on the label, unless otherwise directed by your doctor. To do so may increase the chance of side effects.

Dosing—

The dose of tizanidine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of tizanidine. If your dose is different, do not change it unless your doctor tells you to do so.

• For oral dosage form (tablets):
  • For muscle relaxation:
    • Adults—The dose is 8 milligrams (mg) every six to eight hours as needed. No more than 36 mg should be taken within a twenty-four-hour period.
    • Children—Use and dose must be determined by your doctor.

Missed dose—

If you miss a dose of ZANAFLEX, and you remember within an hour or so of the missed dose, take it as soon as you remember. However, if you do not remember until later, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store ZANAFLEX:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.