Chlorzoxazone (250mg) + Diclofenac (50mg) + Paracetamol (500mg) (Medical Monograph)

Overview

A fixed-dose combination (FDC) analgesic, anti-inflammatory, and centrally-acting muscle relaxant. Primarily used for the short-term management of acute, painful musculoskeletal conditions. It provides synergistic action: Diclofenac reduces inflammation and pain at the peripheral site, Paracetamol provides central analgesic and antipyretic effects, and Chlorzoxazone relieves muscle spasm by acting on the spinal cord and subcortical areas of the brain.

The combination exerts a multi-modal action. Diclofenac inhibits cyclooxygenase (COX-1 and COX-2) enzymes, reducing prostaglandin synthesis responsible for pain, inflammation, and fever. Paracetamol's mechanism is complex; it likely inhibits central COX isoforms (COX-2, COX-3) and modulates the endocannabinoid and serotonergic pathways, providing analgesic and antipyretic effects with minimal peripheral anti-inflammatory action. Chlorzoxazone acts primarily at the level of the spinal cord and subcortical areas of the brain by inhibiting polysynaptic reflexes involved in producing and maintaining skeletal muscle spasm.