Background: Because a GABAergic hypofunction has been implied in the pathophysiology of mania, we have tested the antimanic properties of the GABA transporter 1 inhibitor tiagabine.
Method: An open trial was conducted in 8 acutely manic inpatients with DSM-IV bipolar I disorder, 2 of them with tiagabine monotherapy and 6 with tiagabine as an add-on to previously insufficient mood-stabilizing medication. The study duration was 14 days. Changes in psychopathology were assessed by the Bech-Rafaelsen Mania Rating Scale.
Results: None of the patients showed clear-cut relief from manic symptoms during the 2-week observation period. In 2 patients, we saw pronounced side effects (nausea and vomiting in one and a generalized tonic-clonic seizure in the other).
Conclusion: The results from this open trial suggest that tiagabine seems to have no pronounced antimanic efficacy compared with standard treatments such as valproate, lithium, or neuroleptics. It also appears that rapid dosage increases for antimanic treatment can cause potentially severe side effects.