Mounjaro Users Urged to Check for Gallbladder Issues

Pharmacists are advising individuals using the weight loss injection Mounjaro to review medication leaflets for potential gallbladder problems, as concerns grow regarding a link between rapid weight loss and this side effect.

Mounjaro, also known as Tirzepatide, received UK licensing for obesity treatment in November 2024, following initial development for type 2 diabetes management. While gallbladder issues are rare – affecting less than one in 100 patients – symptoms such as upper right abdominal pain, pain between the shoulder blades, nausea, vomiting, fever, or jaundice require immediate medical attention. The increasing popularity of these medications means even rare side effects can impact a significant number of people.

The medication functions by activating GLP-1 and GIP receptors, increasing incretin hormones in the body, and reducing the hormone cholecystokinin, which aids gallbladder function. Rapid weight loss, a common result of using Mounjaro, can also contribute to gallbladder problems as the liver releases extra cholesterol into bile, potentially forming gallstones; experts recommend a weight loss of five to 10 percent of starting weight over six months. For more information on gallbladder health, resources are available from the Mayo Clinic.

Jason Murphy, Head of Pharmacy at Chemist4U, stated, “It’s important to remember that serious side effects from taking weight loss injections like Mounjaro…are very rare and impact fewer than one per cent of people.” He further emphasized that the health benefits of weight loss generally outweigh the risks, and clinicians thoroughly assess patient suitability before prescribing, as detailed in Chemist4U’s patient safety protocols.

Officials encourage anyone experiencing concerning symptoms while on Mounjaro to discontinue use and consult a doctor immediately.