Long-Term Therapy of Myoclonus and Other Neurologic Disorders with L-5-Hydroxytryptophan and Carbidopa

Abstract

We evaluated the therapeutic effect of L-5-hydroxytryptophan (L-5HTP), the precursor of serotonin (5-hydroxytryptamine), combined with carbidopa, a peripheral decarboxylase inhibitor, in patients with intention myoclonus and examined the serotonin metabolites in spinal fluid, blood and urine before and during therapy. In 18 patients with intention myoclonus due to anoxia or other brain damage, 11 derived more than 50 per cent overall improvement during treatment with L-5HTP and carbidopa. Spinal-fluid 5-hydroxyindoleacetic acid was 35 per cent lower in patients with intention myoclonus than in controls (P<0.05). Therapy with L-5HTP and carbidopa increased the concentration of serotonin metabolites in urine and spinal fluid.