Chlorzoxazone
Indications
Chlorzoxazone is used for:
Musculoskeletal Pain
Adult Dose
Musculoskeletal Pain
Indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute, painful musculoskeletal conditions
250-750 mg PO q6-8hr
Hepatic impairment: Contraindicated.
Child Dose
Muscle Spasms
20 mg/kg/day PO divided q6-8hr or 600 mg/m²/day PO divided q6-8hr
Renal Dose
Administration
Should be taken with food.
Contra Indications
Hepatic impairment.
Precautions
Patient w/ history of liver disease, porphyria. Pregnancy. Patient Counselling This drug may cause CNS depression, if affected, do not drive or operate machinery. This drug may cause orange or reddish-purple urine colouration. Monitoring Parameters Monitor LFT periodically; assess signs or symptoms of hepatotoxicity.
Pregnancy-Lactation
Interactions
Enhanced CNS effect w/ other CNS depressants. Increased serum concentration w/ disulfiram, isoniazid.
Adverse Effects
Side effects of Chlorzoxazone :
1-10%
Lightheadedness
Dizziness
Drowsiness
Excitement, Paradoxical
Somnolence
Malaise
Rash
Angioneurotic edema
<1%
Gastrointestinal hemorrhage (rare)
Hepatotoxicity (rare)
Anaphylaxis (rare)
Mechanism of Action
Chlorzoxazone is a centrally acting skeletal muscle relaxant w/ sedative effects. It inhibits polysynaptic reflex arcs on the spinal cord and subcortical areas of the brain, thereby reducing skeletal muscle spasm w/ increased mobility of the muscle and relief of pain.