Weight Loss Drugs: Pancreatitis, Vision Loss & Other Risks Explained

Weighing the Risks: New Scrutiny for Weight Loss Drugs Wegovy and Mounjaro

The rising popularity of weight loss medications like Wegovy and Mounjaro has been met with increased scrutiny regarding potential side effects. Recent alerts from the United Kingdom’s Medicines and Healthcare products Regulatory Agency (MHRA) have highlighted rare but serious health concerns associated with these drugs, prompting a closer look at their risk-benefit profile.

Pancreatitis and Fatalities: A Closer Examination

In late January, the MHRA issued a warning about potential links between GLP-1 receptor agonists – the class of drugs that includes Wegovy and Mounjaro – and acute pancreatitis. The agency emphasized the need for both doctors and patients to be aware of the risk, particularly given reports of severe cases. Between 2007 and October 2025, nearly 1,300 cases of pancreatitis were reported to the MHRA in association with these medications, including 19 deaths and 24 cases of necrotizing pancreatitis, a severe form of the condition where pancreatic tissue dies.

Brazil’s national health surveillance agency, Anvisa, has as well recorded suspected cases. Between 2020 and 2025, 145 notifications of suspected pancreatitis, including 6 deaths, were registered.

What Do the Agencies Say?

Despite the alerts, Anvisa maintains that the therapeutic benefits of these medications still outweigh the risks when used as directed. However, they strongly advise anyone experiencing intense and persistent abdominal pain radiating to the back, accompanied by nausea and vomiting, to seek immediate medical attention. Healthcare professionals are advised to discontinue treatment if pancreatitis is suspected or confirmed.

Both Novo Nordisk, the manufacturer of Wegovy, and Eli Lilly, the manufacturer of Mounjaro, acknowledge pancreatitis as a potential, though uncommon, side effect. Novo Nordisk notes that factors like diabetes and obesity – the conditions these drugs are designed to treat – are themselves risk factors for pancreatitis. Eli Lilly recommends patients discuss symptoms with their doctor and discontinue use if pancreatitis is suspected.

Beyond Pancreatitis: Other Potential Risks

Pancreatitis isn’t the only potential concern. A rare but serious eye condition, non-arteritic anterior ischemic optic neuropathy (NAION), which can lead to vision loss, has also been linked to semaglutide, the active ingredient in Wegovy and Ozempic. Investigations by European and American regulatory agencies have established a roughly two-fold increased risk of developing NAION in patients using semaglutide.

Other less common side effects include gallbladder problems (cholelithiasis) and hair loss. Gallbladder issues were reported in 1.6% of Wegovy patients versus 1.1% in the placebo group during trials. Hair loss was reported in 2.5% of Wegovy patients, compared to 1% in the placebo group. Skin sensitivity issues and aspiration during anesthesia are also potential concerns.

The Role of Regulatory Oversight

The recent alerts underscore the importance of ongoing monitoring and reporting of adverse events associated with these medications. Regulatory agencies like the MHRA, Anvisa, and the European Medicines Agency (EMA) play a crucial role in evaluating the safety of drugs and updating guidelines as new information emerges. The EMA’s investigation into NAION, for example, led to the inclusion of this risk in the drug’s labeling.

What Does This Signify for Patients?

The emergence of these potential risks doesn’t necessarily mean these medications are unsafe, but it does highlight the need for informed decision-making and close collaboration between patients and their healthcare providers. Patients should be fully aware of the potential side effects and report any concerning symptoms promptly.

Frequently Asked Questions

• What is pancreatitis? Pancreatitis is inflammation of the pancreas, an organ that plays a key role in digestion. Symptoms include severe abdominal pain, nausea, and vomiting.
• Are Wegovy and Mounjaro the same medication? No, they are different medications, though both belong to the same class of drugs (GLP-1 receptor agonists).
• Should I stop taking my medication if I experience abdominal pain? Yes, you should seek immediate medical attention and discuss discontinuing the medication with your doctor if you experience severe and persistent abdominal pain.
• What is NAION? NAION is a rare eye condition that can cause sudden vision loss.

Pro Tip: Always discuss any new medications or changes to your treatment plan with your healthcare provider. Don’t rely solely on information found online.

Have you or someone you realize experienced side effects from Wegovy or Mounjaro? Share your story in the comments below. To learn more about weight management options, explore our other articles on healthy eating and exercise.