Comparative Pharmacology
Head-to-head clinical analysis: PARAFLEX versus ROBAXISAL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PARAFLEX versus ROBAXISAL.
PARAFLEX vs ROBAXISAL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Centrally acting muscle relaxant; inhibits polysynaptic reflexes at the spinal cord level, possibly by depressing the central nervous system.
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 once daily, may increase to 500 mg twice daily if needed. Maximum 500 mg/day.
Oral: 2 tablets (methocarbamol 750 mg / aspirin 650 mg) 4 times daily.
None Documented
None Documented
Terminal elimination half-life is approximately 2–3 hours, allowing for multiple daily dosing.
Methocarbamol: 1.0–2.0 hours (prolonged in renal impairment); guaifenesin: approximately 1 hour.
Renal excretion of unchanged drug and metabolites accounts for approximately 50% of an oral dose; fecal excretion accounts for about 20%.
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