Parkinson's disease psychosis (PDP) is a common, nonmotor symptom of
Parkinson's disease (PD), which may affect up to 60% of patients and is associated with impaired quality of life, increased healthcare costs, and
nursing home placement, among other adverse outcomes. Characteristic symptoms of PDP include
illusions; visual, auditory, tactile, and
olfactory hallucinations; and delusions. PDP symptoms typically progress over its course from being mild, infrequent, and often untroubling to complex, sometimes constant, and potentially highly disturbing. PDP has traditionally been treated with atypical
antipsychotics (e.g.,
clozapine and
quetiapine) although these are not approved for this indication and
clozapine requires frequent white blood cell count monitoring due to the risk of
agranulocytosis.
Pimavanserin is a newer atypical
antipsychotic with highly selective binding to serotonergic receptors, no evidence for worsening motor symptoms in PD, and no need for white blood cell count monitoring. It is currently the only approved medication indicated for PDP treatment. However, because it was approved relatively recently (2016), clinical experience with
pimavanserin is limited. Case Presentations. A wide variety of representative clinical scenarios are presented, each with distinct variables and complications. Issues addressed include distinguishing PDP from similar symptoms caused by other disorders such as
dementia, coordinating
pimavanserin with other PD medications and with
deep brain stimulation, adapting
pimavanserin dosing for optimal benefit and tolerability, and recognizing variability of PDP symptoms due to patients' changing life circumstances.
CONCLUSIONS: These scenarios provide multiple insights regarding PDP management and the role of
pimavanserin. Effective treatment of PDP may reduce disturbing symptoms of
psychosis, thus improving patient function and quality of life. In addition, effective
pharmacotherapy for PDP may also facilitate the use of other medications needed to treat neurological symptoms of PD (e.g.,
tremor,
bradykinesia, and
dyskinesia), although they may also have adverse effects that contribute to symptoms of PDP.