Abstract : Asenapine is a new atypical antipsychotic. Like other atypicals, asenapine acts as an antagonist at both dopamine D2 and serotonin 5-HT2A receptors. The efficacy of asenapine monotherapy in the treatment of bipolar disorder manic episodes in adults has been demonstrated in two similarly designed randomized placebo-controlled flexible-dose trials of 3 weeks’ duration, using olanzapine as active reference. Asenapine is associated with a good tolerability profile. In particular, asenapine induces a moderate weight gain, and does not increase serum levels of lipids or fasting glucose.