Comparative Pharmacology
Head-to-head clinical analysis: CHLORZOXAZONE versus ROBAXISAL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CHLORZOXAZONE versus ROBAXISAL.
CHLORZOXAZONE vs ROBAXISAL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Chlorzoxazone acts centrally on the spinal cord and subcortical areas of the brain to inhibit multisynaptic reflex arcs involved in producing and maintaining muscle spasm. It may also have some sedative effects.
Methocarbamol is a centrally acting muscle relaxant whose exact mechanism is not fully understood, but it is believed to involve general central nervous system depression and inhibition of polysynaptic reflexes in the spinal cord. Aspirin inhibits cyclooxygenase enzymes (COX-1 and COX-2), reducing prostaglandin synthesis, which provides analgesic and anti-inflammatory effects, and also irreversibly inhibits platelet aggregation.
250-500 mg orally 3-4 times daily, maximum 750 mg 4 times daily.
Oral: 2 tablets (methocarbamol 750 mg / aspirin 650 mg) 4 times daily.
None Documented
None Documented
Clinical Note
moderateChlorzoxazone + Fluticasone propionate
"The risk or severity of adverse effects can be increased when Chlorzoxazone is combined with Fluticasone propionate."
Clinical Note
moderateChlorzoxazone + Haloperidol
"The metabolism of Haloperidol can be decreased when combined with Chlorzoxazone."
Clinical Note
moderateChlorzoxazone + Tenofovir disoproxil
"The metabolism of Tenofovir disoproxil can be decreased when combined with Chlorzoxazone."
Clinical Note
moderateChlorzoxazone + Sulfisoxazole
Terminal elimination half-life approximately 1–2 hours; clinically relevant for muscle relaxant effect duration.
Methocarbamol: 1.0–2.0 hours (prolonged in renal impairment); guaifenesin: approximately 1 hour.
Primarily hepatic metabolism followed by renal excretion of metabolites; <1% excreted unchanged in urine; minor biliary/fecal elimination.
Methocarbamol: renal (primarily as glucuronide and sulfate conjugates, with <2% unchanged); guaifenesin: renal (metabolites, <1% unchanged). No significant biliary/fecal elimination.
Category C
Category C
Skeletal Muscle Relaxant
Skeletal Muscle Relaxant
"The metabolism of Sulfisoxazole can be decreased when combined with Chlorzoxazone."