High-dose pyridoxine in tardive dyskinesia.

The clinical similarities of tardive dyskinesia and 1-dopa intoxication lend support to the post-synaptic hypersensitivity hypothesis in tardive dyskinesia. Pyridoxine, a co-factor in the decarboxylation of dopa, reverses the movement disorder of l-dopa intoxication. Although early studies of pyridoxine in tardive dyskinesia have not been encouraging, the results of the present study suggest that high doses of pyridoxine may reduce the frequency and severity of involuntary movements in tardive dyskinesia.