HTR2A and Parkinson disease: For instance, cholinersterase inhibitors, such as Rivastigmine, have been documented as improving hallucinatory symptoms in PD patients.33 Furthermore, medications targeting other neurotransmitter systems, such as Clozapine, an atypical antipsychotic with both antidopaminergic and antiserotonergic properties as well as Pimavanserin, a serotonin 2A receptor inverse agonist, have also been shown to improve PD-related psychosis.34,35