Fengabine (SL-79,229) is a drug which was investigated as an antidepressant but was never marketed.

[1][2] Its mechanism of action is unknown, but its antidepressant effects are reversed by GABAA receptor antagonists like bicuculline and it has hence been labeled as GABAergic; however, it does not actually bind to GABA receptors, nor does it inhibit GABA-T.[1][2] In clinical trials, fengabine's efficacy was comparable to that of the tricyclic antidepressants, but with a more rapid onset of action and much less side effects.

[3][4][5] Notably, fengabine lacks any sedative effects.

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