Observations on nicotinic acid therapy in Hartnup disease.

Abstract
The effect of nicotinic acid on tryptophan metabolism was studied in 2 cases [human] of Hartnup disease. No correction of the metabolic abnormalities was observed after an extended period of nicotinic acid therapy, though there was a suggestion of improvement in some of the abnormal findings. Further studies in this disorder are required before treatment with higher than replacement doses of nicotinic acid for long periods of time can be recommended.