THE EFFECT OF GABAPENTIN ON BRAIN GAMMA-AMINOBUTYRIC-ACID IN PATIENTSWITH EPILEPSY

Gabapentin has come into clinical use as adjunctive therapy in the tre atment of epilepsy. Designed to mimic gamma-aminobutyric acid (GABA), its mechanism of action remains elusive. In vivo measurements of GABA in human brain were made using H-1 magnetic resonance spectroscopy. We used a 2.1-T magnetic resonance imager-spectrometer and an 8-cm surfa ce coil to measure a 13.5-cm(3) volume in the occipital cortex. GABA l evels were measured in 14 patients enrolled in an open-label trial of gabapentin. GABA was elevated in patients taking gabapentin compared w ith 14 complex partial epilepsy patients, matched for antiepileptic dr ug treatment. Brain GABA levels appeared to be higher in patients taki ng high-dose gabapentin (3,300-3,600 mg/day) than in those taking stan dard doses (1,200-2,400 mg/day). Gabapentin appears to increase human brain GABA levels.