Eli Lilly’s Zyprexa (olanzapine) and AstraZeneca’s Seroquel (quetiapine fumarate) are both blockbuster medications which are part of a class of drugs known as “atypical” antipsychotics. They are commonly used to treat symptoms of schizophrenia, but have also been widely used for other conditions like bipolar disorder, dementia, autism and obsessive-compulsive disorders.
Both drugs have previously been linked to a number of serious side effects, including severe weight gain, diabetes and pancreatitis. However, a new study published in the October 2008 issue of the journal Schizophrenia Research raises the potential for concerns about a small increased risk of coronary heart disease associated with the drugs.
Researchers from Johns Hopkins University analyzed data from a study funded by the National Institute of Mental Health (NIMH), known as CATIE (Clinical Antipsychotic Trials of Intervention Effectiveness) . They looked at the use five different antipsychotics by people with schizophrenia, analyzing the impact on participants’ 10-year coronary heart disease risk.
In addition to Zyprexa and Seroquel, the other three medications included in the study were other atypical antipsychotics, Risperdal (risperidone) and Geodon (zipraidone), as well as perphenazine, which is an older antipsychotic.
Generally, individuals with schizophrenia have high rates of heart disease, high blood pressure and diabetes. Coronary heart disease, or CHD, results from a failure of coronary circulation to supply adequate blood flow to cardiac muscle and surrounding tissue.
The data from the study suggested that Zyprexa and Seroquel increased the risk of coronary heart disease 0.5% and 0.3%, respectively. In contrast, the other three drugs actually decreased the heart disease risk. Perphenazine decreased the risk by 0.5%, Risperdal and Geodon decreased the risk of CHD by 0.6%.
Researchers suggested that physicians should consider the relative cardiovascular side effects of Seroquel and Zyprexa compared to other drugs, when choosing an antipsychotic treatment for their patients. This is especially important for elderly patients who are often given these drugs, and those with existing cardiovascular risk factors.
Zyprexa and Seroquel have been the subject of intense litigation in recent years as a result of the diabetes and pancreatitis side effects of the drug. Eli Lilly and AstraZeneca have also been accused of widely promoting the “off-label” use of the drugs for uses that were not approved by the FDA as safe or effective, which is illegal.
There are currently over 8,700 Seroquel lawsuits pending against AstraZeneca with the first trials scheduled to begin in February 2009. Approximately 30,000 Zyprexa lawsuits filed against Eli Lilly have been settled to date, with payments exceeding a total of $1.2 billion.