Ibuprofen (400mg) + Paracetamol (325mg) + Chlorzoxazone (250mg) (Medical Monograph)

Overview

A fixed-dose combination analgesic, antipyretic, and centrally-acting skeletal muscle relaxant. Ibuprofen is a non-steroidal anti-inflammatory drug (NSAID) providing anti-inflammatory and analgesic effects. Paracetamol (Acetaminophen) is a centrally-acting analgesic and antipyretic. Chlorzoxazone is a centrally-acting muscle relaxant that acts primarily at the spinal cord and subcortical levels of the brain. This combination is specifically formulated for the symptomatic relief of painful musculoskeletal conditions associated with muscle spasm, such as back pain, sprains, and strains.

The combination works synergistically via three distinct mechanisms. Ibuprofen inhibits cyclooxygenase (COX-1 and COX-2) enzymes, reducing prostaglandin synthesis responsible for pain, inflammation, and fever. Paracetamol's exact mechanism is not fully elucidated but is believed to involve central inhibition of prostaglandin synthesis, possibly via a COX-3 variant, and modulation of the endocannabinoid and serotonergic systems. Chlorzoxazone acts primarily at the spinal cord and subcortical levels of the brain by inhibiting polysynaptic reflex arcs involved in producing and maintaining skeletal muscle spasm.