Effects of tiagabine on cholecystokinin-tetrapeptide (CCK-4)-induced anxiety in healthy volunteers.

There is increasing evidence that a dysregulation of the gamma-aminobutyric acid (GABA) system plays a role in the pathophysiology of panic disorder. Selective enhancement of GABAergic neurotransmission has been shown to improve anxiety in experimental animals and in patients with panic disorder. Tiagabine is an antiepileptic drug, which increases GABA via selective blockade of GABA reuptake. Apart from its anticonvulsant activity anxiolytic properties could therefore be suggested. To investigate the putative anxiolytic properties of the GABA reuptake blocker tiagabine, we studied the impact of tiagabine treatment on cholecystokinin tetrapeptide (CCK-4)-induced panic. Fifteen healthy volunteers received 15 mg tiagabine daily for 1 week. A CCK-4 challenge was performed before and after treatment. Panic was assessed using the API- and PSS-score. There was a marked improvement of CCK-4-induced panic after 1 week of treatment. Both API- and PSS-scores showed a significant reduction. Our results suggest anxiolytic properties of tiagabine in humans, which provide sufficient rationale to assess its putative anxiolytic effects in patients with panic disorder under controlled conditions.