Brilaroxazine (developmental code names RP-5063 and RP-5000), also known as oxaripiprazole, is an investigational atypical antipsychotic which is under development by Reviva Pharmaceuticals for the treatment of schizophrenia and schizoaffective disorder. Reviva Pharmaceuticals also intends to investigate brilaroxazine for the treatment of bipolar disorder, major depressive disorder, psychosis/agitation associated with Alzheimer's disease, Parkinson's disease psychosis, attention deficit hyperactivity disorder (ADD/ADHD), and autism. As of May 2015, it is in phase III clinical trials for schizophrenia.
Brilaroxazine is described as a so-called "dopamine-serotonin system stabilizer" due to its unique actions on the dopamine and serotonin neurotransmitter systems compared to other antipsychotics. Specifically, it acts as a partial agonist of the D2, D3, and D4 receptors and of the 5-HT1A and 5-HT2A receptors, and as an antagonist of the 5-HT6 and 5-HT7 receptors. Brilaroxazine has high affinity for the D2S, D2L, D3, D4.4, 5-HT1A, 5-HT2A, 5-HT7, and H1 receptors, and moderate affinity for the D1, D5, 5-HT3, 5-HT6 receptors, the serotonin transporter, and the α1B-adrenergic receptor. It lacks significant affinity for the 5-HT1B, 5-HT2C, α2-adrenergic, and muscarinic acetylcholine receptors, as well as for the norepinephrine and dopamine transporters.
Brilaroxazine is identical to aripiprazole in chemical structure except for the replacement of one of the carbon atoms in aripiprazole's quinolinone ring system with an oxygen atom, resulting instead in a benzoxazinone ring system. The drug is also closely related structurally to brexpiprazole and cariprazine.