Comparative Pharmacology
Head-to-head clinical analysis: CHLORZOXAZONE versus CYCLOBENZAPRINE HYDROCHLORIDE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CHLORZOXAZONE versus CYCLOBENZAPRINE HYDROCHLORIDE.
CHLORZOXAZONE vs CYCLOBENZAPRINE HYDROCHLORIDE
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.
Cyclobenzaprine is a centrally acting muscle relaxant that reduces tonic somatic motor activity at the supraspinal level, primarily at the brainstem reticular formation and descending pathways. It is structurally related to tricyclic antidepressants and inhibits reuptake of norepinephrine and serotonin, but the direct relationship to its muscle relaxant effects is not fully established.
250-500 mg orally 3-4 times daily, maximum 750 mg 4 times daily.
Adults: 5 mg orally three times daily; may increase to 10 mg three times daily based on response. Maximum 30 mg per day.
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.
Terminal half-life: 18–24 hours (range 8–37 hours). Clinical context: requires multiple doses to achieve steady state (5–6 days); active metabolite norcyclobenzaprine has half-life ~30 hours.
Primarily hepatic metabolism followed by renal excretion of metabolites; <1% excreted unchanged in urine; minor biliary/fecal elimination.
Renal: ~50% as unchanged drug and metabolites; Fecal: ~40% primarily as metabolites; Biliary: minimal.
Category C
Category A/B
Skeletal Muscle Relaxant
Skeletal Muscle Relaxant
"The metabolism of Sulfisoxazole can be decreased when combined with Chlorzoxazone."