Before Using This Medicine

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 this medicine, make sure your doctor knows if you are pregnant or if you become pregnant.

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

Children—Studies on this medicine 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

Other medical problems—The presence of other medical problems may affect the use of tizanidine. Make sure you tell your doctor if you have any other medical problems, especially:

• 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