Intravenous chlormethiazole in the management of primary trigeminal neuralgia resistant to conventional therapy.

The therapeutic efficacy of 0.8% chlormethiazole, administered as 3-10 intravenous infusions each lasting 5-6 h on alternate days, was assessed in an uncontrolled study of 16 patients, aged 44-82 years, with primary trigeminal neuralgia. Prior to entry into the study, patients showed a high frequency of neuralgic paroxysms (20-70 attacks/day) which were refractory to high dosages (1600-2000 mg/day) of carbamazepine. After treatment with chlormethiazole neuralgic paroxysms no longer occurred in five patients, were considerably reduced in intensity and frequency (less than or equal to 5 attacks/day) in six patients, moderately improved in two patients, slightly improved in one patient and showed no change in two patients. The relatively small number of cases and short post-treatment follow-up period limit the conclusions which can be drawn. These results indicate, however, that infusion with chlormethiazole is effective in the treatment of primary trigeminal neuralgia in patients for whom conventional therapy has been unsuccessful.