Open-label dose-titration safety and efficacy study of tizanidine hydrochloride in the treatment of spasticity associated with chronic stroke

Background and Purpose - Spasticity is a frequently observed motor impairment that develops after stroke; it can cause pain and disability in those affected. The objective of the present study was to evaluate the safety and efficacy of tizanidine, a centrally acting α₂-adrenergic agonist, in the treatment of stroke-related spasticity. Methods - Forty-seven patients, who were a minimum of 6 months poststroke and had significant spasticity, were studied at 4 centers. Tizanidine was administered in an open-label maimer for 16 weeks, beginning at 2 mg/d and slowly titrated to a maximum of 36 mg/d. The Modified Ashworth Scale, muscle strength testing, functional assessments, and Pain and Functional Spasticity Questionnaires were administered at baseline and at 4, 8, 16, and 18 weeks (after 1 week off tizanidine). Results -Spasticity was significantly improved between baseline and week 16, with a decrease in total upper extremity Modified Ashworth Scale score of 2.80±0.47 (P<0.0001). No decline in strength was noted. Treatment with tizanidine resulted in a significant improvement in pain intensity (P=0.0375), quality of life (P=0.0001), and physician assessment of disability (P=0.0001). The most frequent side effects were somnolence (62%) and dizziness (32%). No serious adverse events were considered to be drag related. Ten of 47 patients (21%) were able to reach the maximum daily dosage of 36 mg. Conclusions - Overall, the data suggest that tizanidine is safe and efficacious in the treatment of stroke-related spasticity, preserving muscle strength while reducing muscle tone and painful spasms in affected patients.