Medical behemoth Johnson & Johnson is looking down the barrel of mass legal action over the accusations that their drug Risperdal can cause male breast growth — and that the company failed to adequately warn the public of this risk. New accusations from the former head of the FDA allege that Johnson & Johnson was aware of this risk for more than a decade.

Risperdal is an atypical antipsychotic. This means that Risperdal belongs to the newer-generation of drugs for schizophrenia, and is designed to have fewer side effects than the earlier drugs used to treat schizophrenia and related psychiatric ailments.

However, Risperdal lawsuits have alleged that Risperdal side effects may be serious in and of themselves. Among the alleged Risperdal side effects are gynecomastia, or male breast growth.

Gynecomastia is a condition in which males grow female-like breasts. This condition can happen whenever a male has a higher-than-normal level of prolactin in their body.

In healthy females, prolactin is a hormone that promotes breast growth. But when it appears in abnormally-high levels in males, it can cause gynecomastia. Laboratory tests have shown that Risperdal can promote increased prolactin levels in males taking the drug. This has led to a surge of Risperdal lawsuits alleging that Risperdal can cause male breast growth.

Recent statements by a former commissioner of the FDA may further erode Johnson & Johnson’s position in Risperdal lawsuits. According to David Kessler, who was FDA commissioner between 1990 to 1997, the makers of Risperdal found evidence that Risperdal could cause male breast growth.

Statements by Kessler indicated that a study by Janssen Pharmaceuticals, the subsidiary of Johnson & Johnson that makes Risperdal, found that some of the trial patients taking Risperdal experience gynecomastia. Specifically, the Janssen Pharmaceuticals study found that 3.8% of males taking the drug had suffered male breast growth.

So many Risperdal lawsuits have been filed that the legal system has resorted to a process called multidistrict litigation, or an MDL. In MDLs, a single court coordinates tens, hundreds, or even thousands, of individual Risperdal lawsuits together.

This allows courts to avoid duplication of efforts by having precedents set in early cases. MDLs may also lead to settlements after these first trials are held, since these cases are often presumed to be indicative of how the rest of the cases in an MDL will go.

The larger Risperdal MDL is In Re: Risperdal Litigation, Case No. 100300296, in the Philadelphia Court of Common Pleas.