Reasons Why the Risk of Gallstones Increases When Using Wegovy and Mounjaro and Prevention Methods

Recently, GLP-1 class obesity treatments such as Wegovy and Mounjaro have been receiving significant attention. However, data has confirmed that the risk of gallstones may increase during the process of using these drugs or during rapid weight loss. According to a video from the health and medical specialty channel HiDoc, the main causes are identified as the disruption of the cholesterol balance in bile and the decrease in gallbladder contraction as food intake decreases during the weight loss process.

Why Cholesterol in Bile Becomes Supersaturated During Weight Loss

When dieting, as fat in the body is broken down, the fats stored in the liver turn into cholesterol and flow into the bile. Gastroenterologist Professor Song Byeong-jun explained in the video, "To discharge the incoming cholesterol, the liver secretes more cholesterol into the bile." In this process, a 'supersaturated state' occurs where the cholesterol concentration in the bile becomes excessively high, which serves as the first key point in the formation of gallstones.

Generally, high cholesterol levels in the blood are called hyperlipidemia, but gallstones differ in that the problem is the cholesterol concentration in the bile, not the blood. When weight decreases rapidly due to dieting, the cholesterol concentration in the bile can actually increase, necessitating caution. In other words, one must recognize that blood cholesterol levels and bile cholesterol levels can move separately.

Mechanisms of How Reduced Food Intake and Obesity Treatments Induce Gallstones

Reducing food intake for dietary control, practicing intermittent fasting, or maintaining an extremely low-calorie diet also increases the risk of gallstones. When our body consumes a meal containing fat, a hormone called 'cholecystokinin' is secreted, which induces the gallbladder to contract and discharge bile. However, if fat intake becomes extremely low due to dieting, the gallbladder does not contract sufficiently.

Professor Song Byeong-jun explained, "If bile cannot come out in time and continues to stay inside the gallbladder, the bile becomes concentrated," adding, "Just as sediment forms in stagnant water that does not flow, the components in the bile clump together into crystals and become stones." In particular, GLP-1 class obesity treatments have characteristics that reduce gastrointestinal motility, and they have been proven to increase the rate of gallstone formation by causing less bile secretion and inhibiting gallbladder movement.

To summarize, the risk factors that induce gallstones act in three main directions. First, cases where cholesterol is excessively secreted from the liver into the bile as weight is lost too quickly; second, cases where there is no opportunity for the gallbladder to contract due to low food intake; and third, cases where bile discharge is not smooth due to maintaining an extremely low-calorie diet with almost no fat intake.

Drug Treatment for Gallstones and the Possibility of Preventive UDCA Intake

To treat already formed gallstones, 'UDCA' is used. UDCA plays a role in lowering the cholesterol concentration in the bile and stabilizing the bile, thereby slowly dissolving the cholesterol on the surface of the gallstones. According to the video, small gallstones of 5mm or less showed a probability of more than 70% of dissolving when the medication was taken for about 6 months to 1 year. However, if the size of the gallstone is too large or if the pain is severe, making it an emergency situation, surgical resection may be required rather than drug treatment.

Regarding whether UDCA can be taken together with obesity treatments as a preventive measure when prescribed, Professor Song mentioned, "While direct research data on the combination of obesity treatments and UDCA is still lacking, there is data showing that when UDCA was used on patients who experienced rapid weight loss in the past, the gallstone formation rate decreased by about 30%." Therefore, for high-risk groups or patients who have already suffered from gallstone disease, using UDCA preventively in consultation with a prescribing physician may be helpful.

In the current medical insurance system, there are cases where insurance coverage is available for preventive UDCA use for patients who have undergone the aforementioned surgery or under specific conditions of rapid weight loss (such as more than 5kg per month, etc.), so it is important to plan healthy weight management through consultation with experts. In particular, for patients using the drugs for the treatment of severe obesity rather than for cosmetic dieting, close consultation with medical staff for the prevention of gallstones is essential.