Brazilian health authorities are investigating a surge in reported cases of pancreatitis among patients using popular weight-loss medications like semaglutide and tirzepatide.The Brazilian Health Regulatory Agency (Anvisa) has tracked a steady increase in these suspected adverse events as 2020, wiht 2025 already seeing the highest number of notifications to date. While a direct link has not been established, the rising reports – including six potential fatalities – are prompting closer scrutiny of the safety profile of these widely prescribed GLP-1 receptor agonists.
By Raquel Lopes
Brazilian health authorities are investigating a growing number of suspected pancreatitis cases potentially linked to the use of weight-loss medications, including popular drugs like semaglutide and tirzepatide. The increase in reported adverse events raises concerns about the safety profile of these medications, which have become widely prescribed for both diabetes and obesity management.
The Brazilian Health Regulatory Agency (Anvisa) has recorded a continuous rise in notifications of suspected pancreatitis associated with the use of injectable weight-loss pens from 2020 through December 7, 2025. A total of 145 cases have been reported to the agency’s VigiMed system, which monitors adverse drug events. Six of these reports suggest a possible fatal outcome, though Anvisa has not yet specified the years in which these deaths occurred.
In 2020, only one case was registered. That number climbed to 21 in 2021 and 23 in 2022. The agency reported 27 notifications in 2023, followed by 28 in 2024. So far in 2025, there has been a significant jump, with 45 cases reported – the highest number in the recorded series.
The medications involved belong to a class of drugs known as GLP-1 receptor agonists, which include semaglutide, liraglutide, lixisenatide, tirzepatide, and dulaglutida. These drugs work by mimicking a natural hormone that regulates blood sugar and appetite.
Anvisa emphasizes that reporting an adverse event does not automatically confirm a direct link to the medication, but it is a crucial tool for ongoing safety monitoring. The agency also notes that the total number of suspected pancreatitis cases rises to 225 when including reports from clinical trials, though the dates of these trials have not been released.
Pancreatitis is already listed as a known potential side effect in the drug information leaflets for these medications sold in Brazil. Eli Lilly, the manufacturer of Mounjaro (tirzepatide), stated that its product label warns of the risk of acute pancreatitis and advises patients to consult their doctor immediately if they experience symptoms and to discontinue treatment if pancreatitis is suspected.
“We take reports regarding patient safety seriously and actively monitor, evaluate, and report safety information for all of our medicines,” the company said in a statement.
The reported cases are not limited to Brazil. In January, the United Kingdom’s Medicines and Healthcare products Regulatory Agency (MHRA) reported that some patients had died following severe inflammation of the pancreas linked to obesity and diabetes medications. The MHRA issued a warning to doctors and patients, highlighting the potential for serious complications.
Experts suggest the risk of developing pancreatitis while using these medications remains low. Célio Geraldo de Oliveira Gomes, a gastroenterologist with the Rede Mater Dei de Saúde and the Instituto Alfa de Gastroenteologia at the Universidade Federal de Minas Gerais, suggests the association may be related to “abnormal stimulation of pancreatic cells, altering the secretion and composition of digestive enzymes.”
Bruno Halpern, vice president of the Brazilian Association for the Study of Obesity and Metabolic Syndrome (Abeso) and director of the Department of Obesity at the Brazilian Society of Endocrinology and Metabolism (SBEM), noted that potential effects on the pancreas have been a concern since the initial clinical studies of these drugs began 20 years ago.
Anvisa acknowledges that the reported numbers may be an undercount, as not all cases are reported with complete information, including the brand name of the medication. The agency explained that searches conducted using only the active ingredient name may not capture all relevant reports.
