GLP-1 Drug Lawsuits Swell Past 3,600 Cases as Courts Tighten Proof Standards

The cases involve Ozempic, Wegovy, Mounjaro, Zepbound and Trulicity

Federal litigation over the blockbuster class of GLP-1 drugs that includes Ozempic, Wegovy, Mounjaro, Zepbound and Trulicity has ballooned to more than 3,600 pending cases across two multidistrict proceedings, as a federal judge moves to tighten the medical evidence required from patients claiming severe gastrointestinal and vision injuries.

As of mid-April, more than 3,546 cases were pending in MDL No. 3094, the gastrointestinal-injury docket consolidated in the Eastern District of Pennsylvania, up from roughly 3,097 in early January, according to court filings tracked by the Lawsuit Information Center. A separate vision-loss MDL created in December now has at least 73 pending lawsuits and is growing, plaintiffs' firms reported.

The two proceedings, both assigned to U.S. District Judge Karen Marston, target the same group of glucagon-like peptide-1 receptor agonists — drugs originally approved to treat Type 2 diabetes that have become a cultural and commercial phenomenon as weight-loss treatments. The lawsuits accuse Novo Nordisk and Eli Lilly of failing to adequately warn patients and physicians that the medications could cause severe and sometimes permanent injuries.

Neither company has agreed to a global settlement, and bellwether trial scheduling is just getting underway.

Two tracks, two sets of injuries

MDL 3094, consolidated in September 2023, focuses on gastrointestinal injuries, including gastroparesis — a condition often called "stomach paralysis" — as well as ileus, intestinal obstruction, pancreatitis and gallbladder disease, according to court materials posted by the Eastern District of Pennsylvania. Plaintiffs allege Novo Nordisk knew, or should have known, that semaglutide carried a meaningful risk of severe and sometimes irreversible GI complications and did not say so clearly enough on the label, the Spencer Law firm wrote in an April analysis.

The newer proceeding, MDL No. 3163, was created by the U.S. Judicial Panel on Multidistrict Litigation in December 2025 to handle a wave of cases alleging that GLP-1 drugs caused non-arteritic anterior ischemic optic neuropathy, or NAION — a sudden, often permanent vision loss caused by reduced blood flow to the optic nerve. The new docket covers Ozempic, Wegovy, Mounjaro, Zepbound, Saxenda, Victoza, Trulicity and Rybelsus and names both Novo Nordisk and Eli Lilly as defendants, according to a case tracker maintained by Seeger Weiss.

The vision-loss claims gained momentum after a study published in JAMA Ophthalmology found patients prescribed semaglutide developed NAION at more than seven times the rate of patients on other medications.

A higher evidentiary bar

In a ruling that plaintiffs' lawyers say will reshape the litigation, Judge Marston recently held that any plaintiff claiming gastroparesis must back the diagnosis with an objective gastric emptying study — a nuclear-medicine test known as scintigraphy that measures how quickly food leaves the stomach.

"Any plaintiff claiming to suffer (or have suffered) from gastroparesis must show that their diagnosis is based on a properly performed gastric emptying study," Marston wrote in resolving a cluster of Daubert motions, as quoted by the Lawsuit Information Center. The order also kept warranty, labeling, negligence and state-law claims alive, leaving Novo Nordisk and Eli Lilly to defend allegations that they downplayed life-altering side effects in pursuit of market share.

The decision is widely expected to narrow the pool of viable claims by weeding out cases built on symptom reports alone, while clarifying the proof standard for plaintiffs who can produce hard diagnostic results.

Who qualifies?

Plaintiffs' attorneys say the ruling has sharpened the screening criteria they apply to potential clients. Most firms organize the analysis around four pillars: drug exposure, qualifying injury, medical documentation and timing.

To clear the first hurdle, claimants must show verifiable use of a brand-name GLP-1 medication — not a compounded or "research" version — typically through pharmacy printouts, insurance or electronic-health-record data, and physician notes confirming the prescription, according to a guide published by Boesen Law. Off-label use of Ozempic for weight loss does not, by itself, disqualify a patient, Spencer Law noted.

The second pillar — a qualifying injury — depends on which MDL applies. The GI track covers gastroparesis, ileus, intestinal obstruction, pancreatitis, gallbladder disease, cyclic vomiting syndrome, malnutrition requiring hospitalization, pulmonary aspiration during anesthesia and Wernicke's encephalopathy, the Goldwater Law Firm has outlined. Some intake forms exclude ileus diagnoses dated before November 2022, when the FDA label was updated. The vision track covers NAION, sudden vision loss in one or both eyes, sudden blurred or color-vision loss, and persistent dark areas in the visual field, with some firms also evaluating worsening diabetic retinopathy, retinal vein occlusion and macular edema, according to Morris James.

The third pillar — objective documentation — is where many cases now fail. Beyond the gastric emptying study required for gastroparesis claims, attorneys are looking for CT, ultrasound or HIDA imaging for other GI injuries; elevated amylase or lipase for pancreatitis; operative or pathology reports for gallbladder or bowel surgery; and ophthalmologic exams with optic-nerve imaging for NAION cases, Boesen Law has advised. Specialist involvement — a gastroenterologist, hepatologist or ophthalmologist — generally carries more weight than a primary-care note.

The fourth pillar is timing. Lawyers look for a clean sequence in which symptoms began during or shortly after GLP-1 use, with no pre-existing diagnosis of the same condition. Most states impose two- to four-year statutes of limitations on personal-injury and product-liability claims, but apply a "discovery rule" that starts the clock when a patient knew, or reasonably should have known, that an injury was linked to a drug, according to the Defective Drug Site and Zanes Law.

A separate front against compounders

While the personal-injury MDLs grind forward, the manufacturers are pressing their own legal offensive against telehealth companies selling compounded knockoffs of their drugs.

In April 2025, Eli Lilly sued Mochi Health, Fella Health, Willow and Henry Meds, accusing them of marketing "untested, unapproved" compounded versions of tirzepatide — the active ingredient in Mounjaro and Zepbound — and using unlicensed prescribers to dictate patient care, CNBC reported. NPR reported that Lilly accused the companies of mass-marketing slightly altered formulations, including untested oral tablets and drops, in a bid to evade FDA regulation, in a separate report on the suits. Novo Nordisk has filed similar actions against compounding pharmacies marketing its semaglutide products.

What's next

No timeline for global settlement has been announced in either MDL. Most large pharmaceutical multidistrict proceedings resolve within three to six years of consolidation, placing a possible MDL 3094 resolution window between 2026 and 2029, Spencer Law estimated. The bellwether process — a small group of representative cases tried first to inform settlement talks — is in early stages on the GI side, while the NAION docket is still in consolidation and discovery.

For now, both sides are bracing for an expensive fight. Novo Nordisk and Eli Lilly have signaled they will defend their warnings and labels vigorously. Plaintiffs' lawyers, armed with the JAMA Ophthalmology data and Marston's evidentiary framework, say they are prepared to push a growing roster of patients with documented injuries toward trial.