The lawsuits over testosterone-bearing drugs are expected to become so numerous they have been coordinated into a multidistrict litigation, or MDL, that two of the defendants, AbbVie and Abbott Laboratories, want expanded to coordinate testosterone lawsuits filed in both state and federal courts.

The MDL concerns drugs designed to treat a condition called “low-T,” or low testosterone levels. As males age, their bodies produce less androgens, the family of hormones that include testosterone. In some males, this process is more radical than others. These men may experience symptoms like irritability, decreased libido, decreased muscle mass, and other problems. A number of drug makers have made projects designed to treat this condition by replacing androgens like testosterone. However, testosterone product lawsuits have alleged that these drugs can cause serious medical problems.

When a blood clot forms inside the body, it can cause a number of serious medical problems. Such a clot can block the blood supply to critical organs and tissues. Depending on where in the body the blood clot lodges, it can cause different medical emergencies. When the clot lodges in vessels leading to the heart, it can cause a heart attack. Along similar lines, if such a clot lodges in the vessels that feed the brain, it can cause a stroke. Postmarket surveillance and research studies have found that these drugs are linked to an increased risk of blood clot complications including stroke and heart attacks. This includes a November 2013 study published in the Journal of the American Medical Association. This article found that these drugs could exacerbate existing heart problems in older men. In 2014, an article in PLoSOne found similar results, even among younger men with no prior heart problems.

The various lawsuits over these drugs have been coordinated into a single MDL. This allows the legal system to better coordinate these very similar individual lawsuits. This makes a group of individual testosterone lawsuits almost like a single class action lawsuit. In both the MDL and class action lawsuits, tens, hundreds, or even thousands, of individual lawsuits are combined, streamlining the legal process.

AbbVie, one of the defendants in the MDL, has the largest market share of these drugs. AbbVie makes a product called AndroGel, which was the subject of a number of Androgel lawsuits.

The AndroGel MDL is In Re: AndroGel Products Liability Litigation, MDL No. 2545, in the U.S. District Court for the Northern District of Illinois.