Before Using This Medicine

If you are taking this medicine without a prescription, carefully read and follow any precautions on the label. For chlorzoxazone and acetaminophen combination, the following should be considered:

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

Pregnancy—Although studies on birth defects with chlorzoxazone or acetaminophen have not been done in pregnant women, these medicines have not been reported to cause birth defects or other problems.

Breast-feeding—Chlorzoxazone and acetaminophen have not been shown to cause problems in nursing babies. However, acetaminophen passes into the breast milk in small amounts.

Children—Studies on this combination medicine have been done only in adult patients, and there is no specific information about its use in children. However, chlorzoxazone and acetaminophen have been tested separately in children. In effective doses, these medicines have not been shown to cause different side effects or problems in children than they do in adults.

Older adults—Many medicines have not been studied specifically 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 comparing use of chlorzoxazone and acetaminophen combination, or of chlorzoxazone alone, in the elderly with use in other age groups. However, acetaminophen has been tested and has not been shown to cause different side effects or problems in older people than it does in younger adults.

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 chlorzoxazone and acetaminophen combination, it is especially important that your health care professional know if you are taking any of the following:

• Antidepressants, tricyclic (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]) or
• Central nervous system (CNS) depressants (medicines that often cause drowsiness)—These medicines may add to the effects of chlorzoxazone and increase the chance of drowsiness or other side effects

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

• Alcohol abuse or
• Allergies (asthma, eczema, hay fever, hives) or
• Hepatitis or other liver disease or
• Kidney disease—The chance of side effects may be increased