Novo Nordisk A/S drugs that are commonly used for weight loss were linked to a higher risk of bowel obstructions and other gastrointestinal side effects in patients with obesity than an older treatment.
Using a health database, researchers compared side effects from Novo’s drugs such as Ozempic, Wegovy and Saxenda with those of a weight-loss medication called Contrave. Patients on the Novo drugs, called GLP-1s, were roughly nine times more likely to develop swelling of the pancreas than those taking Contrave. GLP-1 drugs were also associated with higher risks of bowel obstruction and delayed stomach emptying, known as gastroparesis.
The findings, published Thursday in the JAMA medical journal, are consistent with what is known about side effects in patients with type 2 diabetes, but shed new light on potential complications for patients using them for weight loss.
“The risk-benefit calculus for this group might differ from that of those who use them for diabetes,” the study’s authors wrote.
Novo Nordisk said it stands behind “the safety and efficacy of all of our GLP-1RA medicines when used consistent with the product labeling and approved indications” and said the study in JAMA has limitations.
“We recommend patients take these medications for their approved indications and under the supervision of a healthcare professional,” the company said in an email. “Treatment decisions should be made together with a healthcare provider who can evaluate the appropriateness of using a GLP-1 based on assessment of a patient’s individual medical profile.”
Novo Nordisk American depositary receipts rose 0.5% at 11:19 a.m. in New York after briefly dropping after the release of the study results. The receipts have gained about 32% so far in 2023.
Prescriptions for GLP-1 drugs have skyrocketed, putting the medications on track to become some of the best-selling of all time. They have long been used in patients with diabetes, but their long-term effects aren’t well established in patients with obesity or those who use them off-label for weight loss. Ozempic and Wegovy are known to cause some unpleasant side effects such as nausea, diarrhea and vomiting, but their increasing popularity has led to concerns about more serious outcomes ranging from suicidal thoughts to thyroid cancer.
In September, the US Food and Drug Administration added a warning to the label for Ozempic to account for reports of blocked intestines in some patients. That same warning also appears on labels for Wegovy and Eli Lilly & Co.’s diabetes drug Mounjaro that’s frequently used for weight loss.
“Any choice of pharmacological agent to assist with weight loss must be carefully considered, balancing benefits and side effects,” Ian Musgrave, a senior lecturer in the faculty of medicine at the University of Adelaide, said in a statement. Contrave, for example, has a lower risk of GI issues, but is known to have other potential side effects such as seizures and high-blood pressure, he said.