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May 1995

Levorotatory Form of 5-Hydroxytryptophan in Friedreich's Ataxia: Results of a Double-blind Drug-Placebo Cooperative Study

Arch Neurol. 1995;52(5):456-460. doi:10.1001/archneur.1995.00540290042016

Objective:  To study the effect of the levorotatory form of 5-hydroxytryptophan on the cerebellar symptoms of Friedreich's ataxia.

Design:  Cooperative double-blind study of the levorotatory form of 5-hydroxytryptophan vs placebo.

Setting:  Twelve centers in research hospitals. Patients: Twenty-six patients were included; 19 completed the study (mean±SD age of patients, 25.9±8.1 years). Of these 19 patients, eight were treated with placebo and 11 were treated with the drug.

Main Outcome Measures:  A semiquantitative scale for kinetic and static ("postural") cerebellar functions and quantitative measurements of time in standard tests that evaluated stance, speech, writing, and drawing.

Results:  In the active treatment group, a significant decrease of the kinetic score was observed (P=.03), indicating an improvement in coordination.

Conclusions:  These results demonstrated that the levorotatory form of 5-hydroxytryptophan is able to modify significantly the cerebellar symptoms in patients with Friedreich's ataxia. However, the effect is only partial and not clinically major.