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Although Parkinson’s disease is recognized as a movement disorder, the disease is sometimes preceded and frequently accompanied by other cognitive and psychiatric features. Some studies suggest that up to 50% of all patients with Parkinson’s disease will experience hallucinations or delusions at some time during the course of their illness—believed to be in part due to the elevated dopamine levels produced by common Parkinson’s disease medications.
Efforts to treat PDP with antipsychotics commonly prescribed for schizophrenia to date have proven mostly futile (PDP patients taking clozapine experienced worsening Parkinson’s disease symptoms; PDP patients taking quetiapine experienced fewer side effects, but the medication has yet to be proven to be more effective than placebo in these patients). However, pimavanserin is a selective-serotonin inverse agonist that preferentially targets 5-HT2A receptors, while avoiding activity at dopamine and other receptors commonly targeted by antipsychotics.
The FDA’s decision to approve pimavanserin was based on the results of a trial in which adults with PDP were randomly assigned to take 40 mg of pimavanserin or placebo daily for six weeks. Patients taking pimavanserin experienced fewer and less severe hallucinations and delusions without worsening the primary motor symptoms of Parkinson’s disease. The most common adverse effects reported by patients taking pimavanserin included peripheral edema, nausea, and confusional state, according to Acadia Pharmaceuticals Inc., the manufacturer of the medication.
As with other atypical antipsychotic drugs, the FDA noted that Nuplazid will feature a boxed warning indicating the increased risk of death associated with the use of antipsychotics in patients with dementia-related psychosis. Additionally, Nuplazid is not recommended in patients with severe renal impairment.
“[The] approval of Nuplazid represents a major paradigm shift in the treatment of Parkinson’s disease psychosis,” Michael S. Okun, M.D., medical director of the National Parkinson Foundation, said in a press release. “Through its novel and selective mechanism of action, Nuplazid is a breakthrough treatment that works in a whole new way—treating hallucinations and delusions without blocking dopamine receptors and, therefore, not impairing motor function in Parkinson’s psychosis patients.”
According to Acadia, Nuplazid will be commercially available next month.
For related information, see the Psychiatric News article “Will Nuplazid Offer a ‘New’ Choice for Treating Parkinson’s Disease Psychosis?”