Comparative Pharmacology
Head-to-head clinical analysis: ROBAXIN versus ROBAXISAL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ROBAXIN versus ROBAXISAL.
ROBAXIN vs ROBAXISAL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Centrally acting muscle relaxant; depresses polysynaptic reflexes at spinal cord and supraspinal levels, possibly via glycine receptor agonism and GABAergic modulation.
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.
1500 mg orally 4 times daily, or 750 mg orally every 4 hours as needed. Maximum 6 g/day. For IV use: 1 g (10 mL) as a single intravenous injection or infusion.
Oral: 2 tablets (methocarbamol 750 mg / aspirin 650 mg) 4 times daily.
None Documented
None Documented
1-2 hours in adults; clinically, multiple daily dosing required to maintain effect.
Methocarbamol: 1.0–2.0 hours (prolonged in renal impairment); guaifenesin: approximately 1 hour.
Renal excretion of metabolites accounts for 99% of elimination; <1% excreted as unchanged drug in urine.
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