An extended-release injectable formulation of the second-generation antipsychotic aripiprazole (Abilify) has been approved by the FDA (Abilify Maintena – Otsuka/Lundbeck) for once-monthly treatment of schizophrenia. It is the fourth second-generation antipsychotic to become available in a long-acting parenteral formulation. Long-acting parenteral antipsychotics, given at intervals of 2-4 weeks, are generally used for patients with a history of relapse due to poor adherence to oral maintenance therapy.

Bipolar disorder is characterized by episodes of mania, hypomania, and depression. Recurrences of manic or (more frequently) depressive symptoms are common. About 15-20% of patients with bipolar disorder die by suicide.

Asenapine (Saphris - Schering-Plough), a dibenzo-oxepino pyrrole, has been approved by the FDA in a sublingual tablet formulation for acute treatment of schizophrenia and manic or mixed episodes associated with bipolar disorder. It is the sixth second-generation antipsychotic approved by the FDA for use in bipolar disorder.

The FDA has approved cariprazine (Vraylar – Actavis), an oral, once-daily, second-generation antipsychotic, for treatment of schizophrenia and for acute treatment of manic or mixed episodes associated with bipolar I disorder.

Tetrabenazine (Xenazine - Ovation Pharmaceuticals), an old drug first synthesized 50 years ago for treatment of schizophrenia, was recently approved by the FDA for the treatment of chorea associated with Huntington's disease. It has been available in other countries for decades.

The FDA has approved a sublingual film formulation of the alpha-2 adrenergic receptor agonist dexmedetomidine (Igalmi — BioXcel Therapeutics) for acute treatment of agitation associated with schizophrenia or bipolar I or II disorder in adults. It is the first alpha-2 agonist and the only sublingual film to be approved for this indication. Dexmedetomidine has been available for many years in an injectable formulation (Precedex) for sedation in the intensive care unit and to facilitate procedures such as mechanical ventilation.

Oral antipsychotic drugs used for treatment of schizophrenia, schizoaffective disorder, delusional disorder, and other manifestations of psychosis or mania are listed in Table 1. Parenteral antipsychotic drugs used for treatment of these disorders are listed in Table 2.

Changes caused by one drug in the absorption, distribution, metabolism or excretion of another may lead to a pharmacokinetic adverse drug interaction (DN Juurlink et al, JAMA 2003; 289:1652). Additive drug interactions, such as vasodilation caused by both sildenafil (Viagra) and nitrates, can also have adverse effects.

The FDA has approved lumateperone (Caplyta — Intracellular Therapies), an oral second-generation antipsychotic, for once-daily treatment of schizophrenia in adults. It is the 13th second-generation antipsychotic drug to be approved by the FDA for this indication.