Emerging drugs for bipolar depression: an update.

INTRODUCTION

The acute management of bipolar depression presents particular challenges. In most cases, it responds poorly to traditional antidepressants - chronicity and partial response are commonly observed. In a subset of patients, antidepressants provoke a switch into mania and/or cause rapid cycling over the long term.

AREAS COVERED: The evidence supporting emerging and existing pharmacological treatments for bipolar depression, with particular reference to response and remission rates and risk of switching into mania, is reviewed. Novel modes of action and future pharmacological strategies are considered.

EXPERT OPINION: Drugs with greater efficacy, tolerability and speed of action are required in the treatment of bipolar depression. Novel antidepressant agents, including NMDA antagonists, GABA-ergics, 5HT-7 and 5HT-2 antagonists and adjunctive dopaminergics, offer promise, perhaps with a low risk of switching. Newer dual-action antidepressants (e.g., milnacipran) may have good efficacy but the risk of switching is not known. More randomized controlled trials and naturalistic studies are required.