Real Life Pharmacology - Pharmacology Education For Health Care Professionals

Pimavanserin is an atypical antipsychotic approved for the treatment of hallucinations and delusions associated with Parkinson’s disease psychosis. Unlike traditional antipsychotics, it does not block dopamine receptors, making it a unique option for patients with Parkinson’s disease who are highly sensitive to dopamine antagonism. Mechanism of Action Pimavanserin works primarily as a selective serotonin 5-HT2A inverse agonist and antagonist, with minor activity at 5-HT2C receptors. This dopamine-sparing effect is the key reason it does not worsen motor symptoms in Parkinson’s disease. Adverse Effects The most commonly reported side effects include peripheral edema, nausea, confusion, and hallucinations. QT interval prolongation is a clinically important concern, especially in patients with existing cardiac risk factors. Somnolence may occur but is generally less prominent compared with dopamine-blocking antipsychotics. Warnings and Precautions Pimavanserin carries a boxed warning for increa