Treatment of tension-type headache with tizanidine hydrochloride : its efficacy and relationship to the plasma MHPG concentration

SYNOPSIS Seventy-eight patients with tension-type headache (TH) were treated with tizanidine hydrochloride(tizanidine). Plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) and serum free fatty acids (FFA) levels in thesepatients were determined before the treatment with tizanidine. Eighteen healthy volunteers composed thecontrol group. Four weeks after the treatment with tizanidine 24 (31%) of 78 patients showed excellentimprovement (excellent group); 28 (35%) showed moderate improvement (moderate group); 18 (23%) showedmild improvement (mild group); 7 (10%) showed no improvement and one (1%) showed worsening of herheadache (no change and worsened group). The plasma MHPG levels in the excellent group were significantlyhigher than in the other groups, including the control group. The serum FFA levels in the excellent group weresignificantly higher than in the controls.In this study, 66% of the patients reported improvement in their headaches. Some patients with TH had highplasma MHPG levels and these patients in particular showed excellent improvement after the administration oftizanidine. Though there may be a placebo response to some extent, the clinical usefulness of tizanidine for THseems to be excellent. Further study is necessary concerning the pharmacological effect of tizanidine andplasma MHPG levels in patients with TH.