Zanaflex has been approved as an oral treatment for muscle spasticity. It is indicated for the management of increased muscle tone associated with spasticity, a condition affecting the central nervous system (CNS) causing muscle stiffness and rigidity. Spasticity can occur as a result of many CNS disorders, particularly multiple sclerosis ad spinal cord injury.

In double-blind, placebo-controlled clinical studies Zanaflex was shown to provide significant relief of spasticity symptoms without causing muscle weakness, which can leave patients unable to perform normal daily activities. Additionally, reported side effects did not include evidence of withdrawal effects. Both weakness and potential withdrawal effects can be characteristic of certain currently approved treatment regimens.

Spasticity is an abnormal increase in involuntary muscle tone caused by damage to the CNS and is characterized by painful muscle spasms as well as muscle stiffness and rigidity. Advanced spasticity, in the worst cases, can leave patients bed-ridden and unable to move without assistance.