Use of asenapine as add-on therapy in the treatment of bipolar disorder: a comprehensive review and case series

Introduction: Several randomized controlled trials (RCTs), conducted in schizophrenic and bipolar patients, have documented the efficacy and tolerability of asenapine as monotherapy both for short- and long-term treatment. However, evidence on its augmentative use is more limited and related to the manic/mixed phase of bipolar disorder (BD).

Areas covered: The present article reviews augmentative asenapine efficacy and safety/tolerability in the treatment of BD. It also includes some original cases of bipolar patients treated with add-on asenapine in the short- and long-term.

Expert opinion: To date, only a single RCT with manic/mixed patients with partial response to mood-stabilizer monotherapy supports the efficacy and safety/tolerability of augmentative asenapine to lithium/valproate, both in acute and long-term treatment. Additionally, two case reports confirm the overall effectiveness of augmentative asenapine to clozapine and valproate. Our case series, consisting of 4 bipolar patients treated with adjunctive asenapine to mood stabilizers and atypical antipsychotics – with treatment duration ranging from 1 to 14 months – provided clinical results that are consistent with literature data. Taken as a whole, available evidence seems to support the efficacy and safety of adjunctive asenapine in bipolar patients, though additional studies with active comparators are requested to confirm the current body of evidence.     

The Incidence of Akathisia in the Treatment of Schizophrenia with Aripiprazole,Asenapine and Lurasidone: A Meta-Analysis

Akathisia is a troubling side effect that leads to non-adherence with antipsychotic regimens. Second generation antipsychotics (SGAs) tend to cause less akathisia than older agents but the risk still exists and rates vary between agents. Little is known about the incidence of akathisia among the newer SGAs. The purpose of this study was to conduct a meta-analysis of akathisia incidence rates for three of the newer SGAs: aripiprazole, asenapine, and lurasidone. Data were drawn from published and unpublished clinical trials comparing the drug of interest to either placebo or another SGA in adults with schizophrenia. Twenty-four studies (11 aripiprazole, 5 asenapine, and 8 lurasidone) provided incidence rates for akathisia and related nervous system events. Data showed that the relative risk (RR) of akathisia was double that of controls, with lurasidone having the highest individual RR at 2.7 [CI: 2-3.6]. Sensitivity analysis changed the RR of akathisia to less than 10%. The RR of akathisia was still elevated (1.75 [1.4-2.1]) when these drugs were compared only to actives (older SGAs). Agitation and anxiety RRs were also higher with the newer SGAs as compared to the older SGAs. Previous theory suggests antagonism of serotonin (5-HT)2A receptors may decrease akathisia risk. Expectations were that aripiprazole, asenapine and lurasidone would have a low incidence of akathisia, as all display strong antagonism at 5-HT2A. However, in this study all three had a significantly higher risk of akathisia compared to placebo or other SGAs. This suggests the pathophysiology of akathisia involves other receptors and is multifactorial.