Clonazepam seems to be an effective drug in idiopathic trigeminal neuralgia. Electrophysiological investigations support the idea that this neuralgia is due to a loss of central inhibition. During the first 1-2 weeks of treatment marked drowsiness is observed in the majority of cases. In one case, presence of a synergism between Clonazepam and L-dopa+ inhibitor was also observed.