(FDA approved in bold)

• Schizophrenia
  
• Recent suicidal behavior in patients with schizophrenia or schizoaffective disorder
  
• Psychosis in patients with Parkinson’s disease (PD) or dementia with Lewy bodies (DLB)
  
• Bipolar disorder (treatment resistant)
  
• Severe psychosis

• Blocks D2 receptors similar to other antipsychotics, but also blocks serotonin 2A receptors, which improves motor side effects and perhaps depression and cognitive problems. Also blocks alpha adrenergic receptors, and has anticholinergic and antihistamine effects. May stimulate serotonin 1A receptors

• Psychosis – may be effective in days, more commonly takes weeks or months to determine best dose and achieve best clinical effect

• Continue to use at lowest required dose with appropriate monitoring. Patients with PD and DLB may improve more than patients with schizophrenia

• Increase dose
  
• In psychosis related to PD or DLB, eliminate or reduce dose of offending medications, such as dopamine agonists or amantadine

• PD and DLB: cholinesterase inhibitors may improve symptoms (particularly in DLB)

• Obligatory. Prior to starting treatment, obtain CBC, including white count and absolute neutrophil count. Repeat CBC weekly for the first 6 months of treatment, then biweekly for months 6–12 and every 4 weeks thereafter