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22-03-2016 | Parkinson's disease | News | Article

Warning of increased mortality risk for PD patients taking antipsychotics

medwireNews: Researchers have found a more than twofold increase in the risk of death among patients with Parkinson’s disease (PD) who take antipsychotics, particularly typical antipsychotics.

“This medical class needs to be used cautiously in this population”, they urge in JAMA Neurology.

Antipsychotics are already known to increase mortality in patients with dementia, and led to the US Food and Drug Administration authorising “black box” warnings in 2005.

The latest findings of Daniel Weintraub (University of Pennsylvania, Philadelphia, USA) and co-researchers now suggest a possible need to reduce the use of these drugs in PD patients even if they do not have dementia.

In the 180 days after starting antipsychotic treatment, 7877 PD patients aged an average of 76 years were 2.35 times more likely to die than 7877 similarly aged PD patients not taking such treatment.

The patients’ medical records were obtained from a Veterans Health Administration Database and those taking antipsychotics were matched to those not for age, gender, race, presence and duration of dementia, PD duration, delirium, hospitalisation, comorbidities and use of nonpsychiatric medications.

Only 7.7% of PD patients in each group had a dementia diagnosis, the researchers note.

The risk of death varied depending on the type of antipsychotic taken, being greatest for first-generation or typical antipsychotics, which collectively were associated with a 54% greater risk of death, compared with atypical antipsychotics.

About 30% of patients were taking typical antipsychotics and haloperidol was the most common, accounting for 3.6 % of all antipsychotics prescribed. This drug increased the risk of death 5.08-fold versus no antipsychotic use.

The most commonly prescribed atypical antipsychotic, quetiapine, which accounted for 66.9% of antipsychotics prescribed, was associated with a still significant 2.16-fold increased risk compared with no antipsychotic use.

“Prescribing typical [antipsychotics] to patients with PD should be avoided”, say Weintraub and colleagues.

They conclude: “Given that the incidence of PD is increasing worldwide and that psychosis is very common and distressing to patients and caregivers, the development of informed and improved treatment strategies for this condition remains a priority.”

In a related editorial, Mark Baron (Virginia Commonwealth University Healthy System, Richmond, USA) discusses one limitation of the study – vast multisystem contributors to the cause of death, which prevented “clear support for a specific toxic effect”.

PD was the main cause of death among treated patients, at a rate of 53.2% versus 38.6% in patients not taking antipsychotics, suggesting these drugs worsen the condition due to dopamine blockade, but the degree to which this contributes to the increased risk of death “has not been addressed adequately”, says Baron.

He agrees, however, that “[i]f an [antipsychotic] is to be used, atypical agents with the least potential risk for mortality and the lowest associated risk for worsening parkinsonism should be prescribed.”

By Lucy Piper

medwireNews is an independent medical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2016