Patients Are Suing Over Alleged Side Effects of Weight-Loss Drugs

In 2021, Jacqueline Barber agreed to try Ozempic because her doctor swore it would “work wonders” for her diabetes. A few months later, the vomiting started.

Barber, who is 49 and lives in Kentucky, threw up constantly, so much that she started sleeping on the couch with a garbage can beside her every night. But the drug was keeping her blood sugar under control and her endocrinologist didn’t think it could be the cause of such persistent vomiting, so she stayed on it—even as she began “wasting away,” her muscles deteriorating so much that she needed a walker and her front teeth crumbling from exposure to stomach acid. 

Unable to keep food down, Barber’s weight dropped by more than 100 pounds over roughly one year on Ozempic, until her doctors finally agreed she should stop taking the medication. “It was the worst thing I’ve ever experienced in my life,” Barber says. “My family thought I was getting ready to die.” 

Around the same time she stopped taking Ozempic, Barber was diagnosed with gastroparesis: a condition also known as stomach paralysis that causes the stomach muscles to stop moving food through the digestive tract effectively, potentially leading to vomiting and a number of other GI symptoms. Now, more than a year after her diagnosis, Barber still can’t eat normally and gets some nourishment through a feeding tube. She remains weak, barely able to walk around the corner to her sister’s house.

Doctors have told her it’s “impossible” for Ozempic to take such a long-lasting toll, and her medical records list her gastroparesis as “idiopathic”—that is, without a known cause. But Barber feels certain the medication is at the root of her problems. If she had known what was to come, Barber says, she would never have taken Ozempic. “No one would.”

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Millions of people in the U.S.—about 6% of the adult population, according to health-research organization KFF—take Ozempic or a drug like it, including Wegovy, Mounjaro, and Zepbound. These drugs are collectively known as GLP-1 agonists because they mimic the body’s natural hormone GLP-1, which regulates appetite and digestion. The medications control blood sugar and help people eat less, which makes them highly effective treatments for both diabetes (for which Ozempic and Mounjaro are approved) and obesity (the target of Wegovy and Zepbound). They can also slash risks of heart attack, stroke, and chronic disease, studies suggest. And research continues to uncover new and surprising potential uses for GLP-1s, from addiction treatments to fertility boosters.

“Everybody wants to be on these drugs,” which are often seen as “magic,” says Clipper Young, a clinical pharmacist at Touro University California. But there’s a catch.

While most patients take GLP-1 drugs with few or no serious side effects, it's common to experience at least mild gastrointestinal issues like nausea, vomiting, stomach pain, constipation, and diarrhea. In some studies, more than half of patients reported nausea and roughly a third reported vomiting. And as the drugs get more popular, the list of potential side effects is growing longer. Researchers have recently found links between GLP-1 drugs and gastroparesis, intestinal blockage, inflammation of the pancreas, blood clots, and an eye disease that can lead to blindness. Research has also long raised concerns about a potential increased risk of thyroid tumors among susceptible patients.

Dr. Sandeep Palakodeti, a personalized health care entrepreneur who has written about the need for unbiased research and education about GLP-1 drugs, says these emerging reports are "definitely a signal that we need to investigate a little bit more."

It’s not unusual, he says, for new safety concerns to bubble up after a drug is already on the market. If a side effect is rare, it may not arise even in a large, well-designed clinical trial. But once a medication is prescribed to millions of people from all walks of life—not just those who fit the specific patient profile required to participate in a study—it’s likely that some of them will have the misfortune of experiencing a rare complication. Post-approval safety issues arose for a third of novel drugs approved from 2001 through 2010, leading a small number to be pulled from the market and many more to be labeled with additional safety warnings, research shows. Only time will tell if GLP-1 drugs are headed for those fates, Palakodeti says.

Novo Nordisk, the drug company that makes Ozempic and Wegovy, and Eli Lilly, the manufacturer of Mounjaro and Zepbound, do not deny that their drugs cause side effects, most often involving GI discomfort. But, the companies say, these side effects are usually mild to moderate, improve over time, and altogether stop if patients decide to go off their medications—contrary to what patients like Barber argue has happened to them.

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More research is needed to determine whether GLP-1 drugs are actually to blame for complications that some patients have experienced. When millions of people use a medication, some of them are bound to develop health issues while taking it—but that doesn’t necessarily mean their prescription caused the problem.

Still, when someone develops health problems after taking a new drug, their natural reaction is often to blame the medication—and to stop using it. Clinical trial data from Eli Lilly and Novo Nordisk suggest fewer than 10% of GLP-1 study participants dropped out due to side effects. But clinical trials are artificial environments: In the real world, 37% of people using a GLP-1 drug for either diabetes or weight loss had quit a year after starting, according to 2024 research published in JAMA Network Open. People were more likely to have quit if they had developed gastrointestinal side effects, the study found—but insurance hassles and expenses may also be factors, since the drugs can cost more than $1,000 per month out-of-pocket.

Some patients are going further than quitting. Thousands of people who have developed health problems including intestinal blockages, gallbladder damage, and especially gastroparesis after taking GLP-1s have filed, or are expected to file, lawsuits against Novo Nordisk and Eli Lilly, arguing they were not adequately informed about the risks of using these medications, according to court documents associated with those claims.

In a statement to TIME, a spokesperson for Novo Nordisk said the company is "aware of the health challenges that some of these patients have experienced and are sympathetic to their health journey,” but maintained that side-effect lawsuits against the company are “without merit.” A spokesperson for Eli Lilly also said in a statement to TIME that the lawsuits do not have merit and that the company will “vigorously defend against these claims.”

And, in a joint position statement filed in response to those patient lawsuits, representatives for the companies emphasized that their drugs have been assessed and approved by the U.S. Food and Drug Administration and that GLP-1s have been used and studied for “many years.” The drugs’ proven risks are listed on product labels, they wrote. (Neither company made executives available for on-the-record interviews.)

A Pennsylvania judge is overseeing these lawsuits, none of which have gone to trial yet. But the judge has already signaled some willingness to side with the drug companies, in August agreeing to consider their request for stricter standards around proof of diagnosis for patients who claim to have gastroparesis. (Gastroparesis is often misdiagnosed when judged by its symptoms alone, studies show.)

Andrew Van Arsdale, founding attorney at AVA Law Group, a personal-injury firm working with many of those current or potential plaintiffs, says there may be additional cases focused on other alleged side effects, like blindness and blood clots, in the future.

“I just want people to have the education I didn’t,” says Barber, one of Van Arsdale’s clients who, like most plaintiffs in the group, is in the process of suing over gastroparesis. 

Some unpleasantness is an expected and accepted part of medical care, as almost every drug comes with side effects. But as patients like Dana Filmore have learned, the side effects of GLP-1s can become intolerable.

Filmore, who is 55 and lives in Ohio, hates needles, so she wasn’t thrilled by the idea of injecting herself with Ozempic once a week, possibly for the rest of her life. But she wanted to get her diabetes under control, so started taking it in 2021. Filmore felt fine at first. But as her doctors progressively raised her dose, things started to go sideways. 

Eventually, she developed such bad digestive complications—sometimes constipation, sometimes diarrhea and an urgent need to empty her bowels—that she couldn’t go anywhere without first making sure she’d have easy access to a bathroom. Once, she had an accident while driving to work. “I’m 55, and I feel like I need to walk around with Depends on,” she says. “It’s embarrassing.”

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Filmore’s physicians encouraged her to stay on Ozempic for the sake of her diabetes, and she did for a while. But last summer, she decided she’d had enough. Even a year after she stopped, her stomach hasn’t gone back to normal. She says her primary care physician agrees that the drug is probably behind her digestive problems.

Filmore has not yet filed a lawsuit against Novo Nordisk, but she is also working with Van Arsdale’s firm on potential litigation related to her complications.“I just want them to admit that they’re altering people’s lives,” she says.

In legal proceedings, lawyers for the companies have argued that their drugs temporarily and purposely slow digestion but do not cause chronic issues such as gastroparesis, noting that side effects should disappear within about a month of going off the medications. “You stop the medication, the GI side effects go away,” Dr. Lucas Przymusinski, a lawyer and internal-medicine physician representing Novo Nordisk, said during a September presentation of scientific evidence in a Philadelphia court. “That’s how it works.”

Dr. Laura Davisson, director of the Medical Weight Management program at West Virginia University who is not involved in either Barber or Filmore’s care, agrees. She says she’s never seen such a long-lasting case of side effects in her practice. In fact, she often emphasizes to her patients that side effects aren’t permanent. “I always say, ‘It doesn’t really make sense to not get the benefit of a medication because you’re worried about a side effect,’” she says. “‘You don’t even know if you’ll get that side effect, and if that side effect does occur, it’s reversible.’”

Even serious risks aren’t necessarily a reason for regulators not to approve a drug, as long as the medication provides more benefit than risk overall. Drug makers are, however, required to disclose potential dangers—and disclosure is at the heart of patient lawsuits, with users claiming they were not adequately warned about gastroparesis or other complications.

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Mahyar Etminan, a drug safety epidemiologist at the University of British Columbia whose research has shown a connection between GLP-1 medications and gastroparesis, says it’s time for additional warnings about stomach paralysis, given that his study and others suggest increased risk. Regulators have recommended warning labels “with much less data, to be honest with you,” he says. “I’m not sure why there isn’t a warning [for gastroparesis] yet.” (During the September presentation of scientific evidence, representatives for Novo Nordisk noted that Etminan and his co-authors are not gastroenterologists and said their study was not enough to establish cause and effect.)

Eli Lilly’s warning label for Mounjaro says it can cause “severe” gastrointestinal problems and is not recommended for patients with preexisting gastroparesis, but the label doesn’t explicitly list gastroparesis as a possible side effect. The labels for Ozempic and Wegovy don’t specifically mention gastroparesis either, though they do say that vomiting, nausea, diarrhea and other GI symptoms linked to the condition are common.

Przymusinski told the judge overseeing the cases that the FDA has thoroughly reviewed safety and labeling data for GLP-1s and “never has mandated a warning for gastroparesis.” The agency has, however, requested more information about reported side effects and is "evaluating the need for regulatory action." In 2023, the agency added a warning about intestinal blockages to Ozempic’s label.

One complicating factor: gastroparesis can stem from diabetes, the condition that causes many people to start using GLP-1 drugs in the first place. If a patient with mild diabetic gastroparesis starts taking a drug that purposely slows digestion, it’s not a stretch to see how the medication could make their preexisting problem worse, says Young, the clinical pharmacist. But are GLP-1s really at fault for doing exactly what they’re marketed to do—especially if, as the company’s lawyers argue, the drugs aren’t capable of causing permanent damage?

Read More: What to Know About Diabetes and the Risk of Silent Heart Attacks

At this point, Young says, there’s enough data to warrant better screening of patients who may be at risk. But is it fair to say the medications are causing these problems? “We just don’t have long-term data at this point,” he says.

Davisson, the West Virginia obesity-medicine specialist, says most people can tolerate a GLP-1 just fine, as long as they’re counseled on how to manage side effects. The problem, she says, is that many providers can’t perfectly calibrate dosages, diets, and lifestyles to keep people feeling well. In an overburdened system, many providers simply don’t have time to have in-depth, ongoing conversations about side effects with their patients. New scientific research on these medications is also published constantly, and it’s hard for busy clinicians to keep up with it, says Palakodeti, the personalized-medicine physician.

And much of that research is funded by the drug makers themselves (an issue not at all unique to GLP-1s). Studies have found that company-funded research tends to yield more positive results than independently financed studies. Pharmaceutical companies like Novo Nordisk have also spent millions of dollars promoting their drugs to physicians. Consciously or not, Palakodeti says, those influence campaigns can shape the way doctors practice medicine and communicate risks to patients. “When you’re sending a drug rep to the office with lunch for your entire staff, is that drug rep focusing on the positives and the negatives in the same light?” he asks. “Probably not.”

“Novo Nordisk believes that responsible engagement between pharmaceutical companies and the medical community is good for patients and advances care and science,” a company spokesperson said in a statement. “We never influence prescribing decisions, and we abide by all applicable laws and regulations, and our [recent] spend in this area has significantly decreased.” 

Despite the millions of prescriptions and the hundreds of studies that have analyzed GLP-1 drugs, questions remain about how they affect long-term health. More research is needed to know if these drugs are actually causing some of the complications patients are now reporting—and suing over.

Filmore, the Ohio woman who quit using Ozempic because of her GI side effects, says all she wants is clarity, something no one seems able to give her. “Is this something I need to worry about for the rest of my life? Is it going to stop at some point? Is it going to get worse?” she wonders. “I would just like to know what I’m dealing with.”