Chlorzoxazone

What is Chlorzoxazone?

• Chlorzoxazone (Paraflex; Parafon Forte; Strifon Forte; Lorzone) is a centrally acting muscle relaxant used as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute painful musculoskeletal conditions.

Chlorzoxazone

What are the uses of this medicine?

• Chlorzoxazone (Paraflex; Parafon Forte; Strifon Forte; Lorzone) is used as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute painful musculoskeletal conditions.
• It is used in combination with physical therapy, analgesics (such as aspirin or acetaminophen), and rest.

How does this medicine work?

• Chlorzoxazone is a centrally-acting agent for painful musculoskeletal conditions.
• chlorzoxazone acts primarily at the level of the spinal cord and subcortical areas of the brain where it inhibits multi-synaptic reflex arcs involved in producing and maintaining skeletal muscle spasm of varied etiology.
• The clinical result is a reduction of the skeletal muscle spasm with relief of pain and increased mobility of the involved muscles.

Who Should Not Use this medicine ?

This medicine cannot be used in patients with:

• known intolerance to the drug.

What drug interactions can this medicine cause?

• Tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take.

Be sure to mention any of the following:

• sedatives, sleeping pills, tranquilizers, and vitamins

Is this medicine FDA approved?

• Chlorzoxazone was approved for use in the United States in 1958 and is still widely used.

How should this medicine be used?

Recommended dosage: Adult Dosage:

• One tablet three or four times daily.
• If adequate response is not obtained with this dose, it may be increased to 1½ tablets (750 mg) three or four times daily.

Administration:

• Chlorzoxazone comes as a tablet to take by mouth.
• It usually is taken three or four times a day.
• Take chlorzoxazone exactly as directed.
• Do not take more or less of it or take it more often than prescribed by your doctor.

What are the dosage forms and brand names of this medicine?

This medicine is available in fallowing doasage form: As tablet contains:

• Chlorzoxazone 500 mg

This medicine is available in fallowing brand namesː

• Paraflex; Parafon Forte; Strifon Forte; Lorzone

What side effects can this medication cause?

The most common side effects of this medicine include:

• gastrointestinal disturbances
• gastrointestinal bleeding
• Drowsiness
• dizziness
• lightheadedness
• malaise
• skin rashes
• petechiae
• ecchymoses
• Angioneurotic edema or anaphylactic reactions
• discoloration of the urine

What special precautions should I follow?

• Serious (including fatal) hepatocellular toxicity has been reported rarely in patients receiving chlorzoxazone. Patients should be instructed to report early signs and/or symptoms of hepatotoxicity such as fever, rash, anorexia, nausea, vomiting, fatigue, right upper quadrant pain, dark urine, or jaundice. Chlorzoxazone should be discontinued immediately and a physician consulted if any of these signs or symptoms develop.
• The concomitant use of alcohol or other central nervous system depressants may have an additive effect.
• Chlorzoxazone should be used with caution in patients with known allergies or with a history of allergic reactions to drugs. If a sensitivity reaction occurs such as urticaria, redness, or itching of the skin, the drug should be stopped.
• Chlorzoxazone has been linked to rare instances of acute liver injury, a few of which have been fatal. If any symptoms suggestive of liver dysfunction are observed, the drug should be discontinued.
• 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.

What to do in case of emergency/overdose?

Symptoms of overdosage may include:

• nausea
• vomiting
• diarrhea
• drowsiness
• dizziness
• lightheadedness
• headache
• malaise
• loss of muscle tone
• Respiratory depression
• Low blood pressure

Management of overdosage:

• In case of overdose, call the poison control helpline of your country. In the United States, call 1-800-222-1222.

• Overdose related information is also available online at poisonhelp.org/help.
• In the event that the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services. In the United States, call 911.
• Gastric lavage or induction of emesis should be carried out, followed by administration of activated charcoal.
• Thereafter, treatment is entirely supportive.
• If respirations are depressed, oxygen and artificial respiration should be employed and a patent airway assured by use of an oropharyngeal airway or endotracheal tube.
• Hypotension may be counteracted by use of dextran, plasma, concentrated albumin or a vasopressor agent such as norepinephrine. Cholinergic drugs or analeptic drugs are of no value and should not be used.

Can this medicine be used in pregnancy?

• Chlorzoxazone should be used in women of childbearing potential only when, in the judgment of the physician, the potential benefits outweigh the possible risks.

Can this medicine be used in children?

• Use and dose must be determined by your doctor.

What are the active and inactive ingredients in this medicine?

Active ingredient:

• CHLORZOXAZONE

Inactive ingredients:

• SILICON DIOXIDE
• CROSCARMELLOSE SODIUM
• DOCUSATE SODIUM
• MAGNESIUM STEARATE
• CELLULOSE, MICROCRYSTALLINE
• SODIUM BENZOATE
• D&C YELLOW NO. 10
• FD&C BLUE NO. 1
• ALUMINUM OXIDE

Who manufactures and distributes this medicine?

MANUFACTURED BY:

• BARR LABORATORIES, INC.
• POMONA, NY

What should I know about storage and disposal of this medication?

• Store at controlled room temperature 15º-30ºC (59º-86ºF).

Muscle relaxants

• Baclofen
• Carisoprodol
• Chlorzoxazone
• Cyclobenzaprine
• Dantrolene
• Metaxalone
• Methocarbamol
• Orphenadrine
• Tizanidine

• Dailymed label info on Chlorzoxazone
• FDA Chlorzoxazone

Muscle relaxants

• Baclofen
• Carisoprodol
• Chlorzoxazone
• Cyclobenzaprine
• Dantrolene
• Metaxalone
• Methocarbamol
• Orphenadrine
• Tizanidine

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