Pharmacodynamics and pharmacokinetics of the oral antispastic agent tizanidine in patients with spinal cord injury.

The efficiency and duration of action of a single oral dose (8 mg) of tizanidine in patients with spinal cord injuries were determined by studying its antispastic, cardiovascular and sedative effects along with its pharmacokinetic profile in five tetraplegic and five paraplegic patients. After the administration of tizanidine, there was a reduction in spasticity in both groups within half an hour, with the effects lasting for 3 to 4 hours. There was no rebound increase in blood pressure.