A growing number of women allege that the cholesterol-reducing drug caused serious side effects that the drug company knew about, but failed to warn users. Lawsuits from women claiming Lipitor caused their type-2 diabetes have climbed from 56 to about 1,000 over the past five months, reported Reuters.

Lipitor is the biggest-selling prescription drug of all time. The drug, which lost its patent protection in 2011, has sold more than $130 billion worldwide and has over 29 million patients in the U.S. who have been prescribed the drug.

The U.S. Food and Drug Administration said in 2012 that Lipitor and other statins could prompt memory loss and a slight increased risk of diabetes. The lawsuits followed. Lawyers for the women said that women are more vulnerable to these side effects and gain less benefit from the drug.

Pfizer “has at all times provided physicians with accurate information regarding the benefits and potential risks of Lipitor in the medicine’s FDA-approved label,” said the company’s spokesman Steve Danehy.

A federal judicial panel consolidated the Lipitor diabetes cases into a Federal courthouse in Charleston, S.C, which prompted a spike in the lawsuits. Pfizer fought the consolidation because the drug maker felt it would encourage more copycat lawsuits.

Statins work by blocking the liver’s production of cholesterol, which in turn reduces the risk of heart disease. When it made its warning in 2012, the FDA said that the cardiovascular benefit “outweighs this small increased risk” for diabetes, according to a statement.

The company denies the claims that Lipitor caused their new onset diabetes, which is “a medical condition that is highly prevalent in the patient population prescribed statins, and we intend to vigorously defend against the allegations,” Danehy said.

The outcome of the cases, the first of which is scheduled for next July, will hinge on if the heart benefit of the medicines outweighs the risk from an increased chance of diabetes.