Older Antipsychotic Drugs Pose Heart Risk
By Emma Hitt, PhD Reuters Health December 13, 2001

NEW YORK (Reuters Health) - Antipsychotic medications may dramatically
increase the risk of sudden cardiac death, although newer forms of these
drugs introduced after 1994 may not be as harmful as older forms, according
to researchers.

Antipsychotics, the primary treatment for schizophrenia and certain other
mental disorders, are thought to increase what is known as the ``QT''
interval, which heart specialists can determine from the peaks and valleys of
an electrocardiogram printout. A prolonged QT interval is believed to
increase the risk of developing abnormal heart rhythms.

``We had anecdotal evidence that these medications caused cardiac deaths, but
this has not been investigated on a such large scale before,'' Dr.
Purushottam Thapa, of the University of Arkansas in Little Rock, told Reuters
Health.

Thapa and colleagues studied nearly 500,000 Medicaid patients, including many
who were taking antipsychotics. They report their findings in the December
issue of the Archives of General Psychiatry.

The researchers categorized the patients into four groups: those currently
taking a moderate dose of antipsychotics, those taking a low dose, those who
took them in the past year only, and those who did not take them at all.

After following the patients for an average of about 2.5 years per patient,
the investigators found that 1,487 patients died suddenly from heart problems.

Patients in the moderate dose category, meaning they were taking more than
100 milligrams of thioridazine or the equivalent amount of another drug, were
more than twice as likely to suffer sudden cardiac death as patients not
taking antipsychotics.

Furthermore, patients taking a moderate dose who already had heart problems
had more than triple the risk of sudden cardiac death compared to patients
with heart problems who were not on the drugs, the report indicates.

The investigators also found that patients taking low doses of antipsychotics
or who had stopped taking them had only a slightly increased risk compared
with nonusers.

According to Thapa, the newer antipsychotics, such as risperidone, olanzapine
and quetiapine, are less likely than the antipsychotics evaluated in this
study to cause these side effects.

``The older generation antipsychotics are prescribed only rarely these
days,'' Thapa said. ``The newer antipsychotics may cause these side effects
also, but so far, their effects appear to be milder,'' he added.

``Clinicians should be careful to monitor the heart activity of patients
taking these drugs and could consider prescribing a lower dose of
antipsychotic wherever possible,'' Thapa suggested.

Dr. Carlos A. Zarate, Jr., of the National Institute of Mental Health, who
wrote an editorial accompanying the study, noted that the reason
antipsychotics have this effect is unclear. ``It's probably multifactorial,''
he told Reuters Health.

``Just because of these findings, patients should not stop taking these types
of antipsychotics. However, heart monitoring of these patients should
increase,'' Zarate said.

SOURCE: Archives of General Psychiatry 2001;58:1161-1167, 1168-1171.

http://dailynews.yahoo.com/htx/nm/20011213/hl/risk_1.html