Tizanidine HCl in the preventive treatment of chronic tension-type headache

Objective: To assess the efficacy of tizanidine hydrochloride in the preventive treatment of chronic tension-type headache. Design: This was an open-label, 3-month, flexible-dosing study of tizanidine (2mg to 32mg daily). Patient daily diaries were used to record the number of headache days per 28 day period. Pericranial muscle involvement in headache was determined by palpatory findings of muscle spasm and tenderness. Setting: Diamond Headache Clinic. Patient selection: Adult patients with chronic tension-type headache who were attending the Diamond Headache Clinic were eligible for this study. Main outcome measures: The outcome assessment variable was the number of days with headache per 28 days. This was used to evaluate the comparative response to tizanidine in patients suffering from chronic tension-type headache, with and without pericranial muscle involvement. Result: This study enrolled 61 patients between 20 and 64 years of age (19 men, 42 women; mean age 41.5 years). A diagnosis of pericranial muscle involvement was made for 39 patients. Significantly greater improvement was observed in those patients with pericranial muscle involvement than in those without pericranial muscle involvement, as indicated by a Chi-square analysis (p < 0.001). In patients with pericranial muscle involvement, tizanidine responders received a mean daily dose of 8.4mg compared with 6mg for non-responders. In patients without pericranial muscle involvement, tizanidine responders received a mean daily dose of 8mg compared with 7.6mg for non-responders. No laboratory or physical abnormalities were noted. The only adverse effect reported was tiredness, which occurred in 50 percent of patients. Conclusion: Tizanidine may be an effective agent for the preventive treatment of chronic tension-type headache with pericranial muscle involvement.