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 the skeletal muscle relaxants, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to any of the skeletal muscle relaxants or to carbromal, mebutamate, meprobamate (e.g., Equanil), or tybamate. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Although skeletal muscle relaxants have not been shown to cause birth defects or other problems, studies on birth defects have not been done in pregnant women. Studies in animals with metaxalone have not shown that it causes birth defects.

Breast-feeding—Carisoprodol passes into the breast milk and may cause drowsiness or stomach upset in nursing babies. It is not known whether chlorphenesin, chlorzoxazone, metaxalone, or methocarbamol passes into the breast milk. However, these medicines have not been reported to cause problems in nursing babies.

Children—Studies with the skeletal muscle relaxants have been done only in adult patients, and there is no specific information comparing use of these medicines in children with use in other age groups. However, carisoprodol and chlorzoxazone have been used in children. They have not been reported to cause different side effects or problems in children than they do in adults.

Older adults—Many medicines have not been tested in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information about the use of skeletal muscle relaxants in the elderly.

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 a skeletal muscle relaxant, it is especially important that your health care professional know if you are taking any of the following:

• Alcohol or
• Central nervous system (CNS) depressants or
• Tricyclic antidepressants (amitriptyline [e.g., Elavil], amoxapine [e.g., Asendin], clomipramine [e.g., Anafranil], desipramine [e.g., Pertofrane], doxepin [e.g., Sinequan], imipramine [e.g., Tofranil], nortriptyline [e.g., Aventyl], protriptyline [e.g., Vivactil], trimipramine [e.g., Surmontil])—The chance of side effects may be increased

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

• Allergies, history of, or
• Blood disease caused by an allergy or reaction to any other medicine, history of, or
• Drug abuse or dependence, or history of, or
• Kidney disease or
• Liver disease or
• Porphyria—Depending on which of the skeletal muscle relaxants you take, the chance of side effects may be increased; your doctor can choose a muscle relaxant that is less likely to cause problems

• Epilepsy—Convulsions may be more likely to occur if methocarbamol is given by injection