Link Between Gastroparesis and Ozempic, Other GLP-1 Medications To Be Reviewed by MDL Court in 2026

Side effects of GLP-1 medications like Ozempic, Wegovy, Mounjaro and others have been blamed in lawsuits for causing a number of gastrointestinal problems, such as gastroparesis and intestinal obstruction.

The U.S. District Judge presiding over all Ozempic and Mounjaro gastroparesis lawsuits brought throughout the federal court system has announced that much of the first half of 2026 will be dedicated to addressing two key issues that need to be resolved before the litigation can move on to bellwether trials.

Novo Nordisk and Eli Lilly face nearly 3,000 Ozempic lawsuits, Wegovy lawsuits and Mounjaro lawsuits brought over their failure to warn about gastrointestinal risks associated with their respective lines of glucagon-like peptide-1 (GLP-1) receptor agonists, which are approved for the treatment of diabetes and for weight loss.

GLP-1 medications include the blockbuster diabetes treatments Ozempic and Mounjaro, which have seen a sharp rise in popularity in recent years after being linked to significant weight loss side effects. These benefits prompted drug makers to release dedicated versions of the drugs for weight-loss. Novo Nordisk introduced Wegovy (semaglutide), the weight-loss counterpart to Ozempic, while Eli Lilly launched Zepbound (tirzepatide), the weight-loss version of Mounjaro. Other drugs in the GLP-1 class include Saxenda, Byetta, Victoza, Trulicity, Rybelsus and others.

However, along with surging sales have come concerns over certain side effects being reported by users, particularly involving GLP-1 gastrointestinal problems. These include gastroparesis, or stomach paralysis, and the risk of intestinal obstruction, among others.

All federal GLP-1 gastroparesis lawsuits have been centralized into a multidistrict litigation (MDL) in the Eastern District of Pennsylvania, where U.S. District Judge Karen Marston is overseeing pretrial proceedings, coordinated discovery and plans to prepare a group of representative claims to serve as early test “bellwether” trials.

However, before scheduling those trials, Judge Marston required the parties to address certain “cross-cutting” issues, which would have widespread implications on the litigation.

Early on, Judge Marston directed the parties to prioritize discovery and motions on three key concerns, including whether claims are preempted by federal law, whether plaintiffs are required to present specific diagnostic testing evidence, and whether there is sufficient general causation evidence linking Ozempic and other GLP-1 medications to gastrointestinal injuries.

In August, Judge Marston ruled on the requirements for diagnostic testing, leaving questions over general causation and preemption laws as yet unaddressed. On December 16, she issued a case management order (PDF) setting key deadlines for addressing the issues throughout 2026.

The schedule calls for plaintiffs to serve expert reports by January 2, with a similar deadline for defendants set for February 12. Plaintiffs’ rebuttal expert reports are due by February 23, and all parties must have expert depositions completed by April 10.

Under the pretrial schedule, motions to exclude expert opinions are due by April 28, followed by a deadline of April 30 for summary judgment motions. Briefs opposing expert witness exclusions must be filed by June 3, while opposition briefs to summary judgment motions are due by June 16. Reply briefs supporting expert witness exclusions are due by June 24, and replies in support of summary judgment motions must be filed by July 24.

After resolving the last two cross-cutting issues in 2026, Judge Marston is expected to direct the parties to select several representative Ozempic lawsuits for early bellwether test trials, which will help the parties gauge how juries are likely to respond to evidence and testimony that would be presented throughout the litigation.

While the outcomes of these bellwether trials are not binding on other claims, they could help the parties reach an Ozempic settlement agreement that would avoid the need for each individual case to be sent back to its originating district for costly individual trials in the future.

Ozempic Vision Loss Lawsuits

Alongside the gastrointestinal side effects litigation, a growing number of Ozempic vision loss lawsuits have also been filed against the drug maker, each claiming the manufacturer failed to warn about the risk of non-arteritic anterior ischemic optic neuropathy (NAION). 

NAION is a serious eye condition caused by reduced blood flow to the optic nerve, which transmits visual information from the eye to the brain. The condition can lead to sudden vision changes, blurred or distorted sight, partial vision loss or permanent blindness, often developing without warning.

Last week, the U.S. Judicial Panel on Multidistrict Litigation (JPML) decided to centralize all Ozempic and Wegovy NAION lawsuits before Judge Marston, as part of a separate MDL from the gastroparesis lawsuits. Therefore, the Court is expected to establish a separate schedule for evaluating the link between vision loss and Ozempic later in 2026.

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