Tiagabine: a novel drug with a GABAergic mechanism of action.

The various possibilities for manipulating the gamma-aminobutyric acid (GABA) system to augment GABAergic inhibition have been surveyed with reference to the relevant antiepileptic compounds that have been successfully or unsuccessfully investigated in relation to these different mechanisms of action. The first clinical studies of tiagabine (TGB), a novel GABA-uptake inhibitor are now available. These studies utilized a novel design, the enrichment (Amery) design, which is put into perspective compared to classical clinical trial designs. Possible advantages and disadvantages of TGB, as seen at this stage in development, have been identified.