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31-07-2011 | Parkinson's disease | Article

Alarm raised over antipsychotic use in PD patients

Abstract

Free abstract

MedWire News: Patients with Parkinson's disease (PD) and psychotic symptoms are often prescribed antipsychotic drugs, despite the attendant safety risks, research shows.

Use of antipsychotic drugs in these patients was no different in 2008 than in 2002, report Daniel Weintraub (University of Pennsylvania, Philadelphia, USA) and colleagues. This was despite two US Food and Drug Administration (FDA) warnings, in 2005 and 2008, about the increased morbidity and mortality risk associated with antipsychotic drug use in patients with dementia.

Dementia is a long-term complication for 80-90% of PD patients, say Weintraub et al. "Thus, the risks associated with antipsychotic use in PD may be higher than previously considered."

Their analysis of Veterans Affairs data shows that in the financial year 2008, 56.9% of 793 PD patients with psychotic symptoms and dementia were prescribed an antipsychotic drug, as were 47.0% of 1804 without dementia.

These prescribing rates were similar to the 48.5% rate in 6907 patients with psychotic symptoms and dementia, but without PD.

Most antipsychotics given to the PD patients were of the atypical type, with quetiapine most commonly used - in 38.6% of patients with dementia and 30.5% of those without. The researchers note that this drug is well tolerated by PD patients, but that all three placebo-controlled trials so far conducted have failed to show efficacy against psychotic symptoms in PD patients.

In contrast, clozapine has demonstrable efficacy in PD patients and is recommended by the American Academy of Neurology, they say. Yet just 0.6% of PD patients with dementia and 1.0% of those without were given this drug.

"The length of the application process to get approval from the National Clozapine Center, concern for the rare but potentially life-threatening adverse effect of agranulocytosis, and requirements for routine blood cell count monitoring are likely deterrents to greater clozapine use," the researchers comment in the Archives of Neurology.

Comparison of the findings with data from 2002 showed that antipsychotic drug use was unchanged, despite the FDA warnings.

Use of high-potency atypical antipsychotics declined between 2002 and 2008, whereas use of quetiapine and ziprasidone, and aripiprazole increased. "Thus, there has been a recent shift in antipsychotic use in PD to medications that overall may be better tolerated from a motor standpoint but [are] not clearly more efficacious or safer," concludes the team.

MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

By Eleanor McDermid

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