Antipsychotics Used for Parkinson's Despite Warnings
Doctors Still Prescribe Antipsychotics Despite Risks for Some Parkinson's Patients
July 11, 2011 -- Doctors continue to prescribe antipsychotic drugs to their patients with Parkinson's disease and psychosis, despite "black box" warnings from the FDA linking them to increased risk of death among patients with dementia, a study shows.
A black box warning is the strongest drug warning issued by the FDA.
"My sense is that the black box warnings don't factor into decision making," says study researcher Daniel Weintraub, MD, an associate professor of psychiatry at the University of Pennsylvania.
The study is published in the Archives of Neurology.
The black box warning for antipsychotics says the drugs are associated with an increased risk of death for those with dementia, which is common among people diagnosed with Parkinson's. Some commonly prescribed antipsychotics also worsen symptoms of Parkinson's.
Risperdal (risperidone) and Zyprexa (olanzapine), for example, are two such drugs, and neither has been shown to be very effective. Yet according to the study, nearly 30% of patients with Parkinson's and psychosis take them.
Clozaril (clozapine), the only drug known to be both effective and well-tolerated for treating psychosis in Parkinson's patients, is prescribed to less than 2% of those with the disease.
"The gold standard treatment is also one of the most impractical treatments," says neurologist Hubert Fernandez, MD, a Parkinson's specialist at the Cleveland Clinic's Center for Neurological Restoration.
Because of a rare but potentially deadly side effect of the drug, patients on clozapine must have their blood monitored at regular intervals. That burden discourages many doctors from prescribing the medication.
The alternatives, however, are far from ideal. Abilify (aripiprazole), the third most commonly prescribed antipsychotic, is poorly tolerated by Parkinson's patients. And the most popular drug, Seroquel (quetiapine), has failed to show positive results in three studies.
"Quetiapine is the No. 1 choice without clear evidence that it's effective," says Weintraub.
Lack of Treatment Alternatives
The researchers examined Department of Veterans Affairs patient records from fiscal year 2008, comparing the rates of antipsychotic drug prescriptions among two groups: 2,597 patients with Parkinson's disease and psychosis with and without dementia and 6,907 patients with dementia and psychosis but without Parkinson's disease; 97.3% of the patients studied were men.