Chlorzoxazone
Chlorzoxazone (Paraon Forte DSC, Remular-S)
Chlorzoxazone
(klor- ZOX-ah-zohn) Parafon Forte DSC Remular-S (Rx)

Classification: Muscle relaxant, centrally acting

See Also: See also Skeletal Muscle Relaxants, Centrally Acting .

Action/Kinetics: Inhibits polysynaptic reflexes at both the spinal cord and subcortical areas of the brain. Effects may also be due to sedation. Onset: 1 hr. Time to peak blood levels: 1-2 hr. Peak serum levels: 10-30 mcg/mL (after 750-mg dose). Duration: 3-4 hr. t 1/2: 1 hr. Metabolized in the liver and inactive metabolites excreted in the urine.

Uses: As adjunct to rest, physical therapy, and other approaches for treatment of acute, painful musculoskeletal conditions (e.g., muscle spasms, sprains, muscle strain).

Special Concerns: Use during pregnancy only if benefits clearly outweigh risks. Use with caution in clients with known allergies or a history of allergic reactions to drugs.

Side Effects: CNS: Dizziness, drowsiness, lightheadedness, overstimulation, malaise. Dermatologic: Allergic-type skin rashes, petechiae, ecchymoses (rare). GI: GI upset, GI bleeding (rare). Allergic Reactions: Angioneurotic edema, anaphylaxis (rare). Miscellaneous: Discoloration of urine, liver damage.

Overdose Management: Symptoms: N&V;, diarrhea, drowsiness, dizziness, lightheadedness, headache, malaise, sluggishness. May be followed by marked loss of muscle tone (voluntary movement may be impossible), decreased or absent deep tendon reflexes, respiratory depression, decreased BP. Treatment: Supportive.

Additional Drug Interactions: Isoniazid plasma levels of chlorzoxazone due to liver breakdown.

How Supplied: Tablet: 250 mg, 500 mg

Dosage
?Tablets Skeletal muscle disorders.
Adults: 250-750 mg t.i.d.-q.i.d. with meals and at bedtime; pediatric: 125-500 mg t.i.d.-q.i.d. (or 20 mg/kg in three to four divided doses daily).