DOUBLE-BLIND CROSSOVER STUDY WITH LEVOROTATORY FORM OF HYDROXYTRYPTOPHAN IN PATIENTS WITH DEGENERATIVE CEREBELLAR DISEASES

Objective: To determine whether treatment with the levorotatory form o f hydroxytryptophan (L-5-hydroxytryptophan), a controversial experimen tal drug, can improve the conditions of patients with ataxia. Design: A double-blind crossover study with the levorotatory form of hydroxytr yptophan was performed in 39 patients with degenerative cerebellar dis eases. Setting: Patients were selected from an ongoing prospective fol low-up study at two university hospitals. Patients: We studied 19 pati ents with Friedreich's ataxia, 13 with cerebellar atrophy, and seven w ith olivopontocerebellar atrophy. Intervention: The levorotatory form of hydroxytryptophan was given orally in a dose of 1000 mg/d. Each tre atment phase, with the levorotatory form of hydroxytryptophan or the p lacebo, lasted 10 months, after which the treatment of patients was cr ossed over to the other phase. Main Outcome Measures: Ataxia was docum ented and quantified by using a clinical score, posturography, and mea surement of grip force and the rapid-syllable repetition rate. Result: The levorotatory form of hydroxytryptophan had no significant effect on cerebellar symptoms. Conclusion: Long-term treatment with a high do se of the levorotatory form of hydroxytryptophan does not improve the conditions of patients with ataxia.