Use of Newer Antipsychotic Drugs Doubles Risk of Sudden Cardiac Death

The latest generation of antipsychotic medications used in the treatment of conditions such as schizophrenia and bipolar disorder doubles the risk for patients to suffer sudden cardiac death when compared to those not taking the drugs. A new study has found that these newer antipsychotic drugs are no safer for use in patient therapy than the medications they have essentially replaced. The results of the analysis can be found in the New England Journal of Medicine.

The study, one of the largest to date, revealed that younger patients as well as the elderly face the dangers of sudden cardiac failure and death, whereas previous research had only documented the health risks for elderly patients. Researchers from the Vanderbilt University School of Medicine and Geriatric Research, Education, and Clinic Center located in Nashville, Tennessee analyzed the medical data of almost 280,000 people. The data included that of 93,300 patients who had received either the older or newer versions of antipsychotic drugs, as well as information on 186,600 non-users. Patient ages ranged from 30 to 70 years. Researchers matched the information of two non-users for each user of antipsychotic drugs, all of whom were the same age and sex and having entered the study on the same day.

Older antipsychotic drugs have a long established link to sudden cardiac death and include such medications as haloperidol and thioridazine, which are known to double the risk of sudden cardiac death. These medications have been also been associated with causing involuntary tremors and tics in a number of patients and have therefore been largely replaced by newer medications including Clozaril, Risperdal, Zyprexa and Seroquel that were thought to have a decreased risk of sudden cardiac death. However, the study revealed an increase in risk of more than double for patients using the newer medications when compared to nonusers.

The researchers also discovered that the risk of sudden cardiac death relatively increased with the dosage of all antipsychotic medications. The greatest risk was found in patients receiving 300 milligrams or more of thioridazine daily who were discovered to be five times more likely to suffer sudden cardiac death.

According to the researchers, there were about 3 sudden cardiac deaths for every 1,000 patient-years included in the study among patients taking the antipsychotic drugs. (A patient-year is the equivalent of one patient taking the medication for one year). They reported that although patients taking the newer drugs had a slightly higher death rate than those taking the older medicines, the difference was not statistically significant.

Although the FDA approves drugs for specific uses and drug makers can't promote them for unapproved uses, doctors are allowed to prescribe them for other therapies. These atypical drugs have been approved for treatment schizophrenia, bipolar disorder and irritability that is associated with autism in children as young as 5. However, they are also widely prescribed for dementia in nursing-home patients as well as attention deficit hyperactivity disorder (ADHD) in children.

Dr. Wayne Ray, a professor of preventive medicine at Vanderbilt University and lead investigator stated, “The thinking that these atypical drugs were free of risk of sudden cardiac death seems to be incorrect.” Regarding the increase in risk with larger dosages of the drugs Dr. Ray noted, “It suggests that the drugs, when used, should be used at the lowest possible dose.” He believes that the study will encourage physicians to be more careful about prescribing the newer drugs, as is already the case with prescribing the older medications.