Clinical pharmacology of vigabatrin

1. Upon oral administration vigabatrin is rapidly absorbed. Plasma elimination half-life ranges between 5 and 7 h in normal volunteers. Vigabatrin is eliminated primarily via the kidneys with about 65% of the administered dose found unchanged in the urine within 24 h. Kinetics are dose-linear within the range of usual therapeutic doses. 2. At therapeutic doses in man vigabatrin produces dose-related increases in CSF concentrations of free and total GABA, homocarnosine (the GABA-histidine dipeptide) and beta-alanine. These biochemical changes are consistent with an inhibition of GABA-transaminase activity in brain. 3. Thus, with systemic availability upon oral administration and biochemical activity in the CNS, the prerequisites for potential uses of vigabatrin in neurological disorders have been demonstrated in clinical pharmacological studies.