Isoniazid effects on choreiform movement and on GABA, HVA, and 5-HIAA in CSF

Isoniazid was administered in 4-week open trial in patients with choreiform movement. Gamma-aminobutyric acid (GABA), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) in CSF were measured before and after treatment. Isoniazid did not improve choreiform movement. CSF GABA levels were significantly increased after treatment, but HVA and 5-HIAA levels were not significantly altered. The findings suggest that isoniazid influenced brain GABA metabolism but did not influence dopamine and serotonin metabolism in patients with chorieform movement.