PURPOSE OF REVIEW: In April 2016, the Food and Drug Administration (FDA) 
approved a first-in-class atypical antipsychotic medication called pimavanserin 
for the treatment of Parkinson disease psychosis (PDP). We aim to inform readers 
about its indications, effectiveness, and safety profile.
RECENT FINDINGS: Pimavanserin acts as an inverse agonist at serotonin 5-HT2A 
receptors and has negligible effects on other receptors, thereby avoiding the D2 
receptor antagonism that can potentially worsen motor symptoms. Its FDA approval 
was based primarily on the results of a single randomized, placebo-controlled 
phase 3 trial.
SUMMARY: While pimavanserin appears to be a safe, effective, and well-tolerated 
therapeutic option for PDP, additional clinical trials and open-label extension 
studies are needed to determine the long-term safety and efficacy of this 
promising therapy. In the meantime, prescribers need to be aware of the possible 
adverse effects of pimavanserin including QT interval prolongation and a 
potential to cause a paradoxical worsening of symptoms.