Woman’s Gallbladder ‘Rotted’ After Rapid Weight Loss on Mounjaro

A 38-year-old woman in the United Kingdom experienced severe gallbladder complications, requiring surgery, after losing a significant amount of weight while taking the type 2 diabetes and weight loss medication Mounjaro.

Emma McDonald, of Oxford, began taking Mounjaro in June 2024 to address weight gain following the birth of her daughter and to manage symptoms of polycystic ovary syndrome (PCOS). She lost eight stone (50.8kg) but soon developed “excruciating” indigestion. An ultrasound revealed a gallstone blocking her bile duct and cholecystitis, inflammation of the gallbladder, a condition that can lead to serious complications if untreated. The increasing use of GLP-1 agonists like Mounjaro has prompted greater scrutiny of potential side effects.

Doctors discovered McDonald’s gallbladder was “rotting” and she underwent a cholecystectomy in October to remove the organ. “I was told my gallbladder had gone rotten and Mounjaro was an exacerbating factor – but overall, I’m much healthier now so I don’t have any regrets,” McDonald said. She continues to take a 7.5mg dosage of Mounjaro and has since reduced her weight to 12st 9lbs. The National Institute of Diabetes and Digestive and Kidney Diseases notes women are disproportionately affected by gallbladder issues.

Eli Lilly, the manufacturer of Mounjaro, acknowledges gallstones as a potential side effect in its patient information leaflet. A spokesperson stated the company takes patient safety “extremely seriously” and actively monitors safety information. McDonald hopes her experience will raise awareness of gallbladder problems in women, particularly those with risk factors like PCOS, childbirth, and significant weight loss. You can learn more about Mounjaro side effects here.

Eli Lilly encourages patients to consult their healthcare provider regarding any side effects they may experience and to ensure they are receiving genuine medication.