Lipitor lawsuits against Pfizer Inc. have skyrocketed in the face of allegations that the heart disease medication causes type-2 diabetes in women.

Lipitor type-2 diabetes lawsuits have increased from 56 to almost 1,000 in just five months by women who claim they were never warned by Pfizer of the diabetes risk. The Lipitor lawsuits allege that the type-2 diabetes link is greater for women than for men, while the heart disease medication has fewer benefits for women.

In 2012, the U.S. Food and Drug Administration issued a warning and announced a label change that Lipitor as well as other statin drugs were associated with some memory loss and “a small risk” of diabetes.

In February, the Lipitor lawsuits were consolidated by a federal judicial panel into a multidistrict litigation (MDL) or mass tort and sent to a South Carolina federal court.. There was a spike in the number of Lipitor diabetes lawsuits following that decision.

Pfizer denies liability and plans to defend itself against the allegations. The first bellwether trial in the Lipitor MDL is scheduled to begin in July 2015 before U.S. District Judge Richard Gergel.

These bellwether trials will be used to test the strength of the other Lipitor lawsuits, which may lead Lipitor patients to drop their cases if they are not successful, or force Pfizer to settle with the plaintiffs if they are.

Lipitor hit the market in 1996 and has since become the best-selling prescription drug of all time, bringing in more than $130 billion globally for Pfizer. It has been prescribed to more than 29 million American patients.

While the FDA criticized the best-selling drug for its Lipitor side effects, the federal agency still believes that the benefits outweigh the risks.

“Clearly, we think that the heart benefit of statins outweighs this small increased risk (for diabetes),” said Amy Egan, deputy director for safety at the FDA’s Division of Metabolism and Endocrinology.

“The value of statins in preventing heart disease has been clearly established,” Egan added. “Their benefit is clearly indisputable, but they need to be taken with care and knowledge of their side effects.”

The announcement came after several studies were published showing a link between Lipitor and the onset of type-2 diabetes.

One Lipitor study done at the University of Massachusetts Medical School looked at 154,000 women over a seven year time-span who took Lipitor and found that post-menopausal women over the age of 63 who were taking the cholesterol medication had an almost 50 percent greater likelihood of developing type-2 diabetes when compared with women who didn’t take any statins. This was the conclusion after they took into account factors such as obesity, lack of exercise and age.

Statins work by blocking the liver’s ability to produce cholesterol, which reduces the risk for developing heart disease. They are able to decreased the LDL “bad” cholesterol levels as well as decrease triglycerides, and may help raise HDL, which is the “good” cholesterol.

The Lipitor Diabetes MDL is In Re: Lipitor (Atorvastatin Calcium) Marketing, Sales Practices and Products Liability Litigation (No. II), MDL No. 2502, in the U.S. District Court for the District of South Carolina.