"But the risk of these events is low, and the benefits of the therapy certainly outweighs the small risk," says researcher Sean Hennessy, PharmD, PhD, an epidemiologist at the University of Pennsylvania. "Patients getting these drugs should certainly continue taking them."
In a study published in the Nov. 9 issue of The British Medical Journal, Hennessy and his colleagues report that schizophrenics who are prescribed antipsychotic medications were two to three times more likely to have heart problems than patients who take medications for other illnesses.
The Penn team examined data on 120,000 patients to compare the frequency of heart problems in schizophrenic patients taking Mellaril, Haldol, and other antipsychotics to patients without schizophrenia taking other medications.
"What was surprising about our study was that we thought that Mellaril would be associated with a higher risk than Haldol, but it wasn't," Hennessy tells WebMD. "However, at higher doses it may pose a higher risk, so our advice is that physicians prescribe the lowest dose they can use to control symptoms."
Hennessy's study is not the first to suggest either medication can cause heart problems.
In July 2000, the FDA issued a warning about Mellaril to prescribing doctors and ordered its manufacturer to add a label warning about its tendency to cause irregular heartbeat and sudden death. As a result, Mellaril now should be prescribed only for patients who either cannot tolerate or haven't responded to other antipsychotic drugs.
And in Haldol's prescription instructions, doctors are warned that the drug should be "cautiously" administered to patients with cardiovascular disease. It, too, is known to cause heartbeat irregularities in some patients, but doesn't offer the same stern label warnings as Mellaril.
Antipsychotic medications have been used since the 1950s to reduce the psychotic symptoms of schizophrenia, which affects about 45 million people worldwide and is characterized by delusions, hallucinations, and distorted thinking. Its exact cause is unknown, but researchers know it affects brain chemicals and believe the disease has a strong genetic link. Besides running in families, some experts speculate that prenatal problems, such as intrauterine starvation or viral infections, cause trigger its development.
In one of the most recent studies -- published last month -- another team of Penn researchers speculated that schizophrenia might not be a single disease as traditionally thought, but instead a collection of multiple disorders with similar symptoms that affect the brain differently. -->