Tiagabine (TGB), a recently approved antiepileptic drug (AED), has a specific mechanism of action that is unique among AEDs. A potent AED with linear, predictable pharmacokineties, it inhibits gamma-aminobutyric acid (GABA) reuptake into neurons and glia. Tiagabine does not have any clinically relevant effects on hepatic metabolism or on serum concentrations of other AEDs, nor does it interact with commonly used non-AEDs. The most common side effects of TGB in controlled studies are dizziness, asthenia, somnolence, accidental injury, infection, headache, nausea, and nervousness. These events are usually mild to moderate in severity and generally do not require medical intervention. At dosages of 30-56 mg daily, TGB is an effective add-on treatment for partial seizures. Although patients who have medically refractory epilepsy can be converted to TGB monotherapy, more controlled studies are necessary to confirm the efficacy of TGB as monotherapy and to determine the effective dosage range.