Tizanidine is a muscle relaxant of central skeletal muscle. The main site of action is the spinal cord. The drug reduces resistance to passive movements, suppresses spasm and cramps and improves the strength of active muscle contractions. Tizanidine is quickly and completely absorbed into the digestive tract, into the bloodstream. Excretion mainly occurs by the kidneys. Painful muscle spasm. Spasticity due to multiple sclerosis, damage to the brain and spinal cord.