Chlorzoxazone is used to relieve pain and stiffness caused by muscle strains and sprains. It is used in combination with physical therapy, analgesics (such as aspirin or acetaminophen), and rest.

Chlorzoxazone comes as a tablet to take by mouth. It usually is taken three or four times a day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take chlorzoxazone exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

Before taking chlorzoxazone,

• Tell your doctor and pharmacist if you are allergic to chlorzoxazone or any other medications.
• Tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially sedatives, sleeping pills, tranquilizers, and vitamins.
• Tell your doctor if you have or have ever had liver disease.
• Tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking chlorzoxazone, call your doctor.
• Talk to your doctor about the risks and benefits of taking chlorzoxazone if you are 65 years of age or older. Older adults should not usually take chlorzoxazone because it is not as safe or effective as other medications) that can be used to treat the same condition.
• You should know that this medication may make you drowsy. Do not drive a car or operate machinery until you know how this medication affects you.
• Ask your doctor about the safe use of alcohol during your treatment with chlorzoxazone. Alcohol can make the side effects of this medication worse.

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Chlorzoxazone may cause side effects. Your urine may turn purple or red; this effect is not harmful. Tell your doctor if any of these symptoms are severe or do not go away:

• Upset stomach
• Drowsiness
• Dizziness
• Lightheadedness
• Weakness

If you experience any of the following symptoms, call your doctor immediately:

• Skin rash or itching
• Yellowing of the skin or eyes
• Stomach pain

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration’s (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA’s Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can’t be awakened, immediately call emergency services at 911.

Keep all appointments with your doctor.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.