Comparative Pharmacology
Head-to-head clinical analysis: ORPHENADRINE CITRATE versus ROBAXIN 750.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ORPHENADRINE CITRATE versus ROBAXIN 750.
ORPHENADRINE CITRATE vs ROBAXIN-750
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Orphenadrine citrate is a centrally acting muscle relaxant with anticholinergic properties. Its exact mechanism of action is not fully understood, but it is believed to exert its effects by blocking muscarinic acetylcholine receptors and possibly by acting as an NMDA receptor antagonist. It may also have local anesthetic and antihistaminic properties.
Methocarbamol, the active ingredient in Robaxin-750, is a centrally acting muscle relaxant. Its precise mechanism is not fully understood, but it is believed to cause general central nervous system depression, possibly through inhibition of polysynaptic reflexes at the spinal cord level.
100 mg orally twice daily. Maximum: 250 mg/day.
750 mg orally four times daily (total daily dose 3000 mg).
None Documented
None Documented
Terminal elimination half-life is approximately 14 hours (range 11–20 hours) in adults; may be prolonged in elderly or hepatic impairment.
Terminal elimination half-life: 1-2 hours (methocarbamol); clinical context: short half-life necessitates frequent dosing (q6h) and may lead to fluctuating plasma levels.
Primarily renal excretion of metabolites; less than 10% excreted unchanged. Also undergoes biliary excretion with fecal elimination of conjugates.
Renal: 90-95% as metabolites (mainly conjugated), <1% unchanged; biliary/fecal: minor; <2% eliminated in feces.
Category A/B
Category C
Skeletal Muscle Relaxant
Skeletal Muscle Relaxant