SEIZURE FREQUENCY AND CSF PARAMETERS IN A DOUBLE-BLIND PLACEBO-CONTROLLED TRIAL OF GABAPENTIN IN PATIENTS WITH INTRACTABLE COMPLEX PARTIAL SEIZURES

Gabapentin (GBP) is a non-protein-bound gamma amino acid which is not subjected to metabolic degradation in man. As part of a placebo-contro lled double-blind study, patients suffering from intractable complex p artial seizures with or without secondary generalization were followed with lumbar punctures at baseline and after three months of GBP treat ment (900 mg/day or 1200 mg/day). Cerebrospinal fluid (CSF) was analyz ed for concentrations of GBP, amino acids including GABA, homovanillic acid (HVA), and 5 hydroxyindoleacetic acid (5-HIAA). The results indi cate that there were no changes in the selected amino acids, HVA, or 5 -HIAA after GBP treatment. At steady state the CSF/plasma ratios of GB P ranged from 0.056 to 0.34, indicating that there may be some type of active out-transport of GBP across the blood-brain barrier. No linear relationship was observed between plasma and CSF levels in these pati ents.