Myospaz tablets contains Paracetamol 325mg and Chlorzoxazone 250mg.The two relieve pain and relax the muscles. Paracetamol / Acetaminophen is an analgesic (pain reliever) and antipyretic (fever reducer). It blocks the release of certain chemical messengers in the brain that are responsible for pain and fever. Chlorzoxazone is a muscle relaxant. It works by acting on the centers in the brain and spinal cord to relieve the muscle stiffness or spasm.