2012 APA - IPS: Variations in Weight Gain Found among the Top Three Atypical Antipsychotics

New York, NY — A poster presented at the American Psychiatric Association 64^th Institute on Psychiatric Services comparing weight gain associated with the three most highly prescribed antipsychotic medications yielded important considerations for clinicians concerning metabolic side effects.

Antipsychotics are the top-selling prescription drugs in the United States, with more than two billion prescriptions dispensed each year. Atypical antipsychotics offer lower risk for dystonic symptoms than typical antipsychotics, but carry a major side effect of weight gain, which can negatively impact physical and emotional health. Based on 2008 data, the top three atypical antipsychotics in order of patient use are risperidone, aripiprazole, and quetiapine.

For this study, researchers conducted a literature search and systematic review of all randomized controlled trials (including Medline, psycINFO, clinicaltrials.gov) that included two or three of these agents and reported weight change in male and female patients from ages 4 to 98. More than 1,100 records were screened. However, nearly 1,000 were excluded after abstract review. Ninety-five studies were found to be appropriate; of those, only nine studies, which dated from 2003 to 2009, compared two or three of the agents head-to-head. Further screening ruled out bias or industry influence in the studies. Random effects models were used to calculate weighted mean difference for all outcomes.

“In our analysis of the drugs in these nine studies, we found that among the most commonly prescribed atypicals, quetiapine clearly causes more weight gain than risperiodne, and both of these cause more weight gain than aripiprazole,” said study author Steven W. Powell, MD.

In the study abstract, the authors concluded that “Quetiapine causes more weight gain than risperidone and also leads to a greater increase in total cholesterol levels. Furthermore, both quetiapine and risperidone cause more weight gain than aripiprazole. There is insufficient evidence reflecting differences in glucose levels and blood pressure to draw a comparative conclusion.”

The main implication of the study is that an awareness of which atypical antipsychotic causes the least amount of weight gain allows clinicians to select the most appropriate medication to ensure patient compliance and prevent relapse.

“When prescribing for a patient who is overweight or who has diabetes, it is especially important to consider which drug would have the least impact in terms of weight,” Powell said. “We have seen diabetes caused by these agents, so we now routinely start patients who are already overweight on metformin at the same time that we initiate treatment with one of these atypicals.”

The abstract of this study may be found here.