Atypical Antipsychotic Diabetes Risks May Be Reduced By Vitamin D: Study

For years concerns about a diabetes risk have been associated with side effects of atypical antipschotics, such as Seroquel, Zyprexa, Abilify, Risperdal and other popular drugs. However, the new research suggests that users may be able to reduce that risk by taking vitamin D. 

In a study published last month in the journal Scientific Reports, researchers from Kyoto University in Japan report that Seroquel users who took vitamin D had less of a chance of developing diabetes, and suggested that the findings could affect the same risk seen with other members of a popular class of medications known asatypical antipsychotics.

Seroquel (quetiapine fumarate) has bee a top selling drug for AstraZeneca, generating nearly $5 billion a year in sales at its peak. Originally approved by the FDA in 1997 for the treatment of schizophrenia, it has also been frequently prescribed off-label for uses that were not approved as safe and effective at the time, such as anxiety, obsessive dementia, compulsive disorders and autism.

In 2011, AstraZeneca settled about 23,500 Seroquel lawsuits brought individuals who claimed that the side effects of the drug caused them to develop diabetes, and the host of medical complications associated with the condition. The company paid about $350 million, or about $25,000 per case, to resolve the litigation.

In this latest study, researchers data mined the FDA Adverse Event Reporting System (FAERS) and conducted studies on mice to evaluate the Seroquel diabetes risk and how to mitigate the danger for users.

“We found that patients who had coincidentally been prescribed vitamin D with quetiapine were less likely to have hyperglycemia,” researcher Shuji Kaneko said in a press release. “It’s unusual for vitamin D to be prescribed with quetiapine because it is typically prescribed to treat osteoporosis; in fact, there were only 1,232 cases in the world where vitamin D was prescribed with quetiapine. Data mining proved helpful in locating these cases.”

From the mice studies, researchers determined that vitamin D defends against the insulin-lowering effects of Seroquel, instead of lowering diabetes risk on its own. They determined that Seroquel reduced the amount of an enzyme knwon as PI3K, and vitamin D prevented a reduction in PI3K production.

The researchers said that data mining FAERS could potentially lead to the discovery of other ways to mitigate drug side effects.

“Based on the current results, we propose a novel vitamin D/antipsychotic combination pharmacotherapy in which vitamin D can efficaciously safeguard against antipsychotic-induced hyperglycaemia accompanied by insulin resistance,” the researchers concluded. “Thus, the analysis of rapidly growing databases of clinical adverse events and molecular toxicity can provide insights into the practical management of undesirable adverse drug events, as well as their molecular mechanisms.”