Current Trends on Antipsychotics: Focus on Asenapine

Over the years, both first- (FGAs) and second-generation antipsychotics (SGAs), continue to gain increasing evidence of being effective in the treatment of psychotic symptoms. Currently, they represent the first-line treatment of schizophrenia and bipolar disorder, although they are widely used in psychotic depression and other clinical conditions, such as agitation and/or behavioural disturbances. Despite representing an indispensable tool for the treatment of severe psychotic disorders, they are widely known to have a number of unwanted side effects that the clinician must be aware of, and handle carefully to provide the patient the best available treatment in the short and long-term. However, even with respect to the long-term use of some of the most effective SGAs, it is imperative for clinicians not to overlook the risk linked to the onset of potentially severe metabolic side effects such as weight gain, dyslipidaemia, insulinresistance and type II diabetes. Asenapine is one of the newest SGAs licenced in Europe for the treatment of manic episodes and in the US for schizophrenia. It belongs to the same class of clozapine, olanzapine and quetiapine, sharing with them a rather complex pharmacological binding profile. In fact, asenapine shows a high affinity for the serotonin (5HT) receptor of the type 2A (5HT2A) and to a lesser extent for the dopamine receptor of the type 2 (D2), similar to other SGAs. Asenapine behaves also as an antagonist at the level of 5HT2C, H1 and α2-receptors. Asenapine has been reported to be effective either in monotherapy or in combination with mood stabilers (lithium and valproate) in the treatment of manic or mixed episodes, with a lower propensity to induce, or being followed by, depressive symptoms, when compared to other SGAs. These unique properties may explain the increasing interest towards the use of this drug in mixed states, besides schizophrenia and acute mania. The aim of this paper was at reviewing current data on pharmacological properties and clinical use of asenapine, as well as on possible future indication of this SGA.