About Tizanidine A centrally acting a-2 adrenergic agonist, Centrally acting muscle relaxant (short-acting). Mechanism of Action of Tizanidine This drug is a centrally acting alpha2 agonist at alpha2-adrenergic receptor sites and presumably reduces spasticity by increasing presynaptic inhibition of motor neurons. This results the blocking of nerve impulses (or pain sensations) that are sent to your brain. Indications for Tizanidine 1. Painful muscle spasm associated with static and functional disorders of the spine 2. Following surgery for disc prolapse/osteoarthritis of the hip Interactions for Tizanidine Alcohol & other CNS depressants : CNS effects of tizanidine potentiated.