Quetiapine Linked to More Rapid Onset of Metabolic Disturbances in Elderly Patients

Pam Harrison

March 10, 2010

March 10, 2010 (Savannah, Georgia) — The antipsychotic quetiapine (Seroquel, AstraZeneca) is associated with a more rapid onset of metabolic disturbances than other antipsychotics in elderly patients with no baseline metabolic abnormalities before treatment initiation, according to findings presented here at the American Association for Geriatric Psychiatry 2010 Annual Meeting.

Genevieve Letourneau, MD, University of Montreal, Quebec, Canada, and colleagues found that time to onset of hyperglycemia was significantly shorter among patients treated with quetiapine at 17.5 months compared with patients who were treated with olanzapine at 32.6 months or risperidone at 36.3 months. However, the prevalence of hyperglycemia was the same in all 3 groups over time.

Time to onset of hypercholesterolemia was also shorter and the likelihood of patients becoming hypercholesterolemic higher among those treated with quetiapine at 15.8 months compared with olanzapine at 27.4 months and risperidone at 21.9 months.

Quetiapine was similarly associated with a shorter time to onset and a higher prevalence of hypertriglyceridemia at 20.9 months compared with olanzapine at 21.4 months or risperidone at 25 months.

"This is a naturalistic study, so patients were not randomized; they were given what their physician thought would be best for them," Dr. Letourneau told Medscape Psychiatry.

"But we believe that patients with a higher metabolic risk profile were more likely to be put on quetiapine because there is this general idea that quetiapine is a ‘safer’ drug, so this might explain the faster onset of metabolic disorders in these patients," she added.

Various Illnesses

For the study, investigators followed up 231 outpatients treated with 1 of the 3 antipsychotics for various illnesses, including psychosis, depression, bipolar disorders, or dementia. All patients were 70 years or older, and all had been treated for a minimum of 6 months and were followed up for a maximum of 40 months.

Fasting glucose, lipids, and biometric data, such as weight and abdominal circumference, were monitored every 3 months during the first year of treatment and biannually thereafter.

Patients who had evidence of dyslipidemia or glucose intolerance before the initiation of therapy were excluded from the study. Most patients were taking standard doses of each of the 3 medications.

Overall, investigators found that more than 50% of the study group developed 1 of the 3 metabolic abnormalities by the end of follow-up.

"These are preliminary results, and we are starting to look at the data and the dosages used more closely," said Dr. Letourneau. "But we were really surprised by these results because we were not expecting quetiapine to be associated with the fastest onset of hyperglycemia, and this just shows that metabolic abnormalities have to be taken as seriously in older patients as they are in younger patients and that physicians must discuss the possibility of patients developing metabolic abnormalities before initiating antipsychotic therapy."

Ellen Whyte, MD, University of Pittsburgh Medical Center, Pennsylvania, said the study points to the fact that physicians have to be cautious about the medications they prescribe.

"Some patients still require an antipsychotic medication," she told Medscape Psychiatry, "but the elderly are obviously not protected from the metabolic side effects of these drugs, and we need to continue to monitor patients for these side effects and then manage them either by discontinuing the drug, if possible, or using the lowest possible dose and then managing the medical illness judiciously in conjunction with the primary doctor."

Dr. Letourneau and Dr. Whyte have disclosed no relevant financial relationships.

American Association for Geriatric Psychiatry (AAGP) 2010 Annual Meeting: Abstract NR 20. Presented March 6, 2010.