Chlorzoxazone (By Mouth)

Chlorzoxazone (klor-ZOX-a-zone)

Treats pain and stiffness caused by muscle spasm. Belongs to a class of drugs called muscle relaxants.

Brand Name(s):

Remular-S, Parafon Forte DSC
There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not use this medicine if you have ever had an allergic reaction to chlorzoxazone. You should not use if you have had a recent heart attack, heart failure, a heart rhythm disorder, heart block, or hyperthyroidism (overactive thyroid).

How to Use This Medicine:

Tablet

• Your doctor will tell you how much to take and how often.
• You may take the tablets whole or you may crush the tablets and mix them with a small amount of food or liquid.

If a dose is missed:

• Use the missed dose as soon as possible.
• If it is almost time for your next regular dose, wait until then to use the medicine and skip the missed dose.
• You should not use two doses at the same time.

How to Store and Dispose of This Medicine:

• Store at room temperature away from heat, moisture, and direct light.
• Keep all medicine out of the reach of children.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

• You should not use this medicine if you have used an MAO inhibitor such as Marplan® or Nardil® within the past 14 days.
• Unless approved by your doctor, you should not use antidepressants, sleeping pills, tranquilizers, cold and allergy medicine, pain killers, or other muscle relaxants while using chlorzoxazone.
• Do not drink alcohol while using this medicine.

Warnings While Using This Medicine:

• If you are pregnant or breastfeeding, talk to your doctor before using this medicine.
• Talk to your doctor before using this medicine if you have kidney or liver disease or glaucoma.
• You should not use more of this medicine, or use it for longer periods, than your doctor has ordered.
• This medicine can cause drowsiness or blurred vision. Be careful while driving a car or operating machinery.
• This medicine can sometimes cause your urine to turn an orange or red color. This is normal.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

• Skin rash or itching
• Trouble breathing
• Swelling of face or tongue
• Yellowing of eyes or skin
• Muscle weakness or slurred speech

If you notice these less serious side effects, talk with your doctor:

• Drowsiness, dizziness, clumsiness
• Constipation or diarrhea
• Nausea or vomiting
• Dry mouth
• Heartburn or unpleasant taste

If you notice other side effects that you think are caused by this medicine, tell your doctor.