Mounjaro (Tirzepatide) and Gallbladder Disease: A Severity Grading Rubric

How often does tirzepatide cause gallbladder problems?

Mounjaro is tirzepatide, a once-weekly subcutaneous injection approved, with diet and exercise, to improve glycemic control in adults and children 10 years and older with type 2 diabetes, and to reduce the risk of major cardiovascular events in adults with type 2 diabetes at high risk for them. It is not labeled for weight loss [3].

The Mounjaro label carries an acute gallbladder disease warning. In the adult placebo-controlled trials, acute gallbladder disease (cholelithiasis, biliary colic and cholecystectomy) was reported by 0.6% of tirzepatide-treated patients and 0% of placebo-treated patients. The label adds that cholelithiasis and cholecystitis have also been reported in GLP-1 receptor agonist trials and in postmarketing use. It cautions that adverse reaction rates from different trials cannot be directly compared [3].

A 2023 systematic review and meta-analysis of nine randomized trials, with 6,828 people on tirzepatide and 3,043 controls, found the composite of gallbladder or biliary disease significantly more common with tirzepatide than with placebo or basal insulin: RR 1.97, 95% CI 1.14 to 3.42. The individual outcomes (cholelithiasis, cholecystitis and biliary disease) were not each significantly increased [4].

Other pooled analyses differ by population. A 2025 meta-analysis of 13 trials in 26,894 people with obesity but without diabetes found that semaglutide increased gallbladder-related disorders, particularly cholelithiasis, by more than 2.6-fold (95% CI 1.40 to 4.82), while tirzepatide showed no significant biliary risk [5]. For the wider GLP-1 receptor agonist class, a 2022 meta-analysis of 76 trials and 103,371 patients reported composite gallbladder or biliary disease at RR 1.37 (95% CI 1.23 to 1.52), and RR 2.29 (1.64 to 3.18) in the 13 trials testing these drugs for weight loss [6].

Which severity grading systems apply?

The grading tools that exist describe specific diseases, and they come from gastroenterology and surgery rather than from the drug label.

• Tokyo Guidelines 2018 (TG18) set diagnostic criteria and a severity grading for acute cholecystitis. The 2018 revision adopted the TG13 criteria and grading without modification, noting that the grading had been validated against 30-day overall mortality, length of hospital stay, conversion rates to open surgery and medical costs [1].
• The revised Atlanta classification grades acute pancreatitis as mild, moderately severe or severe. Mild disease has no organ failure and no local or systemic complications and usually resolves in the first week. Moderately severe disease involves transient organ failure, local complications, or worsening of a coexisting illness. Severe disease is defined by organ failure lasting more than 48 hours [2].
• The Japanese Society of Gastroenterology's 2016 evidence-based guidelines cover diagnosis and treatment of cholelithiasis and its complications, including choledocholithiasis and hepatolithiasis. They were developed with the GRADE system and are management guidelines, not a severity scale [7].

The Mounjaro label supplies a trigger for investigation rather than a grade: if cholelithiasis is suspected, gallbladder diagnostic studies and clinical follow-up are indicated [3].

Where each tool applies

Stones or sludge without symptoms. Neither TG18 nor Atlanta addresses this. Ultrasound is the best epidemiological screening method for determining how common gallstone disease is [8]. Risk factors for biliary sludge include pregnancy, certain drugs, total parenteral nutrition and fasting, and rapid weight loss is one of the modifiable risk factors for cholesterol gallstones, alongside obesity and a sedentary lifestyle [8].

Biliary colic. The Mounjaro label counts biliary colic within acute gallbladder disease in its trials [3]. Neither TG18 nor the Atlanta classification has a separate grade for it.

Acute cholecystitis. TG18 is the grading system for this condition [1]. The Mounjaro label does not give a severity scale; it lists cholecystitis among the acute gallbladder events reported in GLP-1 receptor agonist trials and postmarketing use [3].

Acute pancreatitis. The Atlanta classification grades it [2]. The Mounjaro label warns that acute pancreatitis, including fatal and non-fatal hemorrhagic or necrotizing pancreatitis, has been observed with GLP-1 receptor agonists and with Mounjaro [3].

What does the Mounjaro label say to do?

• If cholelithiasis is suspected, the label says gallbladder diagnostic studies and clinical follow-up are indicated [3].
• If pancreatitis is suspected, the label says to discontinue Mounjaro and initiate appropriate management [3].
• The signs the label names for pancreatitis are persistent or severe abdominal pain, sometimes radiating to the back, which may or may not be accompanied by nausea or vomiting [3].