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Chlorzoxazone (By mouth)

Chlorzoxazone (klor-ZOX-a-zone)

Treats pain and stiffness caused by muscle spasm. This medicine is a muscle relaxer.

Brand Name(s):

Lorzone, Parafon Forte DSC, Remular-S

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is not right for everyone. Do not use it if you had an allergic reaction to chlorzoxazone.

How to Use This Medicine:


  • Take your medicine as directed.
  • You may swallow the tablets whole, or you may crush the tablets and mix them with a small amount of food or liquid.
  • Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Drugs and Foods to Avoid:

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

  • Tell your doctor if you drink alcohol or if you are using any medicine that makes you sleepy, such as allergy medicine or narcotic pain medicine.

Warnings While Using This Medicine:

  • Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, or glaucoma.
  • This medicine can cause drowsiness, dizziness, or blurred vision. Be careful when you drive a car or use machines.
  • This medicine can cause your urine to turn orange or red. This is normal.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

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

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Dark urine or pale stools, loss of appetite, nausea, vomiting, stomach pain, yellow eyes or skin
  • Muscle weakness or slurred speech
  • Drowsiness, dizziness, clumsiness

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

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 4/4/2014

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