According to a report in the July issue of Archives of Neurology, one of the JAMA/Archives journals, 50% of patients suffering from Parkinson’s disease (PD) and Psychosis are treated with anti-psychotic (AP) agents. These drugs can aggravate Parkinson symptoms. Despite a warning being issued against the use of these drugs by the FDA their frequency of usage in patients with dementia and PD has not changed.

According to the background information in the article, as many as 45,000 people living in the United States suffering from PD eventually developed psychosis post treatment. Moreover, the authors write “AP use in PD is complicated by its potential to worsen Parkinsonism and limited evidence for efficacy.” PD is associated with dementia and many other complications, which are aggravated by the use of APs. Beginning in 2005, most of the APs were labeled with a “black box” warning sign to indicate the risks associated with their use. In the authors view, “Further study of this issue is critical given both the high prevalence of psychosis in this population and that parkinsonian symptoms and frequent co morbid dementia may make this population more likely to experience adverse outcomes, including mortality, with AP treatment.”

Veterans Affairs data from fiscal year (FY) 2002 and FY 2008 were compared by Daniel Weintraub, M.D, University of Pennsylvania and other colleagues. During the study they examined and compared the rates and predictors of AP specifically, being prescribed for 2,597 patients suffering from PD and psychosis, stratified by dementia status (1,804 without dementia and 793 with dementia), with the data derived from 6,907 patients suffering from dementia and psychosis but with no PD.

The results showed that almost 50% of the patients suffering from PD and psychosis were prescribed with an AP, with most of the prescriptions being given for atypical APs. Patients who were diagnosed with both PD and dementia were also likely to be prescribed more APs than the patients without dementia. It was seen that between FY 2002 and FY 2008, there was no change in the overall rate of AP prescription for patients with PD, but the investigators noticed a fall in the use of some variety of APs with a rise in the use of other drugs.

Furthermore, during the period of study the authors noticed a change in the prescription rate of individual drugs with the overall prescription rate being constant, despite the frequent warnings about the APs risks in patients with dementia.

The authors state:

“Approximately one-third of our PD sample had co morbid dementia, and many more likely had mid cognitive impairment (MCI). This has significant clinical implications in PD given the increased morbidity and mortality associated with typical and atypical AP use in dementia populations.”

Though the prescribing habits have shifted towards the drugs that are better absorbed and tolerated by Parkinson patients, it does not necessarily mean that they are safer or more effective. Lastly, the authors believe that there is a need to conduct more focused studies “to further understand what factors contribute to both overall and specific AP use in this population, and longitudinal studies [to] assess the impact of AP treatment on morbidity, mortality, and progression of parkinsonism.”

“Patterns and Trends in Antipsychotic Prescribing for Parkinson Disease Psychosis”
Daniel Weintraub, MD; Peijun Chen, MD, PhD, MPH; Rosalinda V. Ignacio, MS; Eugenia Mamikonyan, MS; Helen C. Kales, MD
Arch Neurol. 2011;68(7):899-904. doi:10.1001/archneurol.2011.139

Written by Barry Windsor