Can you take Mounjaro with gallstones?

Jump to: Understanding gallstones and weight | Mounjaro’s effects on gallbladder | Safety considerations | Managing risk factors | Monitoring requirements | Alternative options | Frequently asked questions | Take home message

It may be possible to take Mounjaro (tirzepatide) if you have gallstones and your BMI is over 27, but only after individual assessment by a healthcare professional, as careful monitoring is essential¹.

Clinical trials show that gallbladder-related adverse events occur in approximately 0.6% of people taking Mounjaro, with most cases being mild to moderate¹.

However, rapid weight loss – a known risk factor for gallstone formation – requires careful management to minimise complications.

In the UK, gallstones affect 10-15% of adults, making this a common consideration when prescribing weight loss medications².

The key to safe treatment is losing weight at a moderate pace (0.5-1kg / 1-2lbs per week) and monitoring for warning signs.

If you have symptomatic gallstones or a history of gallbladder complications, your doctor may recommend treating the gallstones before starting Mounjaro or choosing an alternative approach to losing weight.

Understanding gallstones and weight loss

UK prevalence and statistics

Gallstones are remarkably common in the UK, affecting approximately 10-15% of adults². Women are twice as likely as men to develop gallstones, with prevalence increasing with age.

Most people with gallstones (80%) never experience symptoms; these are called ‘silent’ or asymptomatic gallstones. Only about 20% will develop symptoms requiring treatment over a 20-year period².

The NHS performs over 70,000 cholecystectomies (gallbladder removals) annually, making it one of the most common surgical procedures³.

Understanding your gallstone status before starting weight loss medication helps determine the safest approach.

Why rapid weight loss increases risk

Rapid weight loss is a well-established risk factor for gallstone formation. When you lose weight quickly, several mechanisms increase gallstone risk:

Cholesterol supersaturation: During rapid weight loss, the liver releases extra cholesterol into bile, which can crystallise into stones.

Gallbladder motility: Extreme calorie restriction can reduce gallbladder contractions, allowing bile to stagnate and form stones.

Bile acid changes: Weight loss alters the balance of bile acids and cholesterol, favouring stone formation.

Research shows that losing more than 1.5kg per week significantly increases gallstone risk compared to losing 0.5-1kg weekly⁴.

Types and risk factors

Understanding gallstone types helps predict risk and management strategies:

How Mounjaro affects gallbladder function

Clinical trial data on gallbladder events

The SURMOUNT clinical trials provide comprehensive safety data on Mounjaro’s gallbladder effects¹:

SURMOUNT-1 findings:

• Gallbladder-related adverse events: 0.6% (Mounjaro) vs 0% (placebo)
• Most events were cholelithiasis (gallstones) or cholecystitis
• Higher doses (10 mg, 15 mg) showed a slightly higher risk than 5 mg
• Most events occurred within the first 20 weeks of treatment

Severity of events:

• Mild to moderate: 85% of cases
• Severe: 15% of cases
• Led to treatment discontinuation: <0.2%
• Required surgery: <0.1%

Mechanism of increased risk

Mounjaro may increase gallstone risk through several mechanisms:

1. Enhanced weight loss: While beneficial overall, the significant weight loss (20-25% in trials) can trigger gallstone formation if too rapid.

2. Altered gallbladder motility: GLP-1 and GIP receptor activation may affect gallbladder contractions, though this effect appears minimal with tirzepatide.

3. Changes in bile composition: Weight loss alters cholesterol metabolism, potentially increasing bile lithogenicity.

4. Reduced caloric intake: The appetite suppression can lead to very low calorie intake, reducing gallbladder stimulation.

Timeline of risk

Based on observed trends in SURMOUNT trials, risk appears to vary over time:

Weeks 1-8: Initial risk period as body adapts to medication and calorie reduction begins.

Weeks 8-20: Period of potentially higher risk – many gallbladder events in trials were observed during this timeframe.

Weeks 20-52: Risk may decrease as the weight loss rate typically slows.

After 52 weeks: Minimal additional risk if weight loss has stabilised.

Note: This timeline represents observed trends from trial data, not established clinical guidance.

Safety considerations for gallstone patients

Who should avoid Mounjaro

Certain gallstone-related conditions may contraindicate Mounjaro use:

Absolute contraindications:

• Current acute cholecystitis
• Biliary obstruction
• Gallstone pancreatitis history
• Severe biliary dyskinesia

Relative contraindications (requires specialist input):

• Multiple symptomatic gallstone episodes
• Large gallstones (>2 cm)
• Porcelain gallbladder
• Concurrent liver disease

Pre-treatment screening

NICE guidelines don’t mandate gallbladder screening before starting GLP-1 medications⁵, but consider assessment if:

High-risk patients:

• Previous gallstone symptoms
• Multiple risk factors present
• Strong family history
• Previous rapid weight loss attempts

Screening options:

• Detailed history and examination
• Liver function tests (may be elevated with gallstones)
• Ultrasound scan if clinically indicated

Risk stratification

*Monitoring frequency represents expert practice suggestions rather than mandated protocol.

Managing gallstone risk on Mounjaro

Optimal weight loss rate

The key to minimising gallstone risk is controlling your weight loss rate:

Recommended targets:

• Week 1-4: 0.5-1 kg per week
• Week 5-12: 0.5-1 kg per week
• After 12 weeks: 0.5-1 kg per week
• Maximum safe rate: 1 kg per week

Strategies to control weight loss rate:

• Start with the lowest dose (2.5 mg)
• Delay dose escalation if losing too quickly
• Ensure adequate calorie intake (maximum 10% deficit)
• Add protein-rich snacks if weight loss exceeds 1 kg/week

Dietary strategies

Specific dietary approaches can reduce gallstone risk during weight loss:

Eat a diet based mainly on whole foods:

• Healthy fats: Include a portion the size of your thumb in each meal from nuts, meat, fish, olive oil, and dairy
• Fibre: Aim for half of your plate to come from vegetables
• Protein: Aim for a portion the size of an open hand in each meal

Foods to moderate:

• Refined sugars and ultra-processed foods
• Take-aways
• Very low-fat diets (<20g daily)
• Prolonged fasting periods

Meal timing:

• Eat 3 balanced meals a day to stimulate gallbladder emptying
• Include some fat at each meal
• Avoid skipping meals despite reduced appetite

Warning signs to monitor

Know when to seek medical attention:

Mild symptoms (contact GP within days):

• Mild upper abdominal discomfort after meals
• Bloating or indigestion
• Nausea without severe pain

Moderate symptoms (see GP urgently):

• Steady pain in the upper right abdomen
• Pain between the shoulder blades
• Nausea with vomiting

Severe symptoms (A&E immediately):

• Severe abdominal pain lasting >5 hours
• Fever with abdominal pain
• Yellowing of skin or eyes (jaundice)
• Dark urine and pale stools

Medical monitoring requirements

Baseline assessments

Before starting Mounjaro with known gallstones:

Essential tests:

• Complete medical history, including gallstone symptoms
• Physical examination
• Baseline weight and BMI
• Liver function tests (ALT, AST, ALP, bilirubin)

Consider if indicated:

• Abdominal ultrasound if symptoms present
• Lipid profile
• Inflammatory markers if previous cholecystitis

Follow-up schedule

The following monitoring schedule represents expert practice suggestions rather than a fixed protocol:

When to pause treatment

Consider temporarily stopping Mounjaro if:

• Biliary colic episodes occur
• Liver function tests become abnormal
• Weight loss exceeds 2 kg per week consistently
• Severe gastrointestinal symptoms develop
• Pending gallbladder surgery

Alternative weight loss options

Other GLP-1 medications

Different GLP-1 medications may have varying gallbladder risk profiles. Note that risks vary depending on population, trial length, and gallstone screening methods:

*Risks vary depending on population, trial length, and gallstone screening methods.

Non-medication approaches

For high-risk patients, consider:

Structured lifestyle programmes:

• NHS Digital Weight Management Programme
• Commercial programmes with NHS partnerships
• Dietitian-led interventions

Surgical options:

• Consider cholecystectomy before weight loss if symptomatic
• Bariatric surgery (includes gallbladder assessment)

When to treat gallstones first

Consider gallbladder surgery before Mounjaro if:

• Recurrent biliary colic (2+ episodes)
• Previous complications (pancreatitis, cholecystitis)
• Large stones (>3 cm)
• Non-functioning gallbladder
• Planning significant weight loss (>20% body weight)

Frequently asked questions

Can I take Mounjaro if I’ve had my gallbladder removed?

Yes, you can safely take Mounjaro after cholecystectomy. In fact, you have no increased risk of gallstone complications since the gallbladder has been removed.

Some people experience looser stools after gallbladder removal, which may be exacerbated by Mounjaro initially.

How quickly will I know if Mounjaro is affecting my gallstones?

Based on trial observations, many gallbladder-related side effects occur within the first 20 weeks of treatment, particularly weeks 8-20 when weight loss is typically most rapid.

However, remain vigilant throughout treatment as symptoms can develop at any time.

Should I have an ultrasound before starting Mounjaro?

NICE doesn’t recommend routine ultrasound screening unless you have symptoms or multiple high-risk factors.

If you’ve had previous gallstone symptoms or have a strong family history, discuss screening with your GP.

What’s the safest rate to lose weight with gallstones?

Aim for 0.5-1 kg per week maximum. This rate minimises gallstone risk while still achieving meaningful weight loss.

If you’re losing faster than this, consider delaying your next dose increase or increasing calorie and protein intake.

Can I take medication to prevent gallstones while on Mounjaro?

Ursodeoxycholic acid can help prevent gallstone formation during weight loss. However, NICE does not recommend its routine use in drug-induced weight loss contexts (only in bariatric surgery under specific protocols). Your doctor might consider it if you’re at particularly high risk or have had previous gallstone complications.

Will losing weight cure my gallstones?

Unfortunately, existing gallstones don’t dissolve with weight loss. However, achieving and maintaining a healthy weight reduces your risk of developing new stones and may reduce symptoms from existing stones.

What diet is best for preventing gallstones on Mounjaro?

A diet based on whole foods that minimises the consumption of ultra-processed foods.

Should I stop Mounjaro if I develop gallstone symptoms?

Contact your healthcare provider immediately if you develop any symptoms. They may recommend pausing treatment, reducing the dose, or investigating further. Don’t stop suddenly without medical advice.

Are women at a higher risk of developing gallstones while taking Mounjaro?

Women already have twice the baseline risk of gallstones compared to men. This risk doesn’t increase further with Mounjaro, but women should be particularly vigilant about maintaining moderate weight loss rates.

Can I restart Mounjaro after gallbladder surgery?

Yes, you can restart Mounjaro after recovering from cholecystectomy (usually 2-4 weeks). In fact, you’ll have a lower risk of complications since gallstones can no longer form.

Take home message

Taking Mounjaro with gallstones may be possible for some people, but requires individual assessment by a healthcare professional and careful monitoring throughout treatment.

It’s essential to lose weight slowly and be mindful of potential warning signs. Patients with symptomatic gallstones often require definitive management before weight loss with medication.

Clinical trials show gallbladder complications affect less than 1% of people taking Mounjaro, with most cases being mild. However, those with existing gallstones need extra vigilance, particularly during the first 20 weeks when risk may be higher based on trial observations.

Remember that while rapid weight loss can trigger gallstone problems, achieving a healthy weight ultimately reduces your long-term risk of gallstones.

With the right approach and close medical supervision, some people with gallstones can benefit from Mounjaro’s weight loss effects.

References

1. Jastreboff AM, et al. (2022). Tirzepatide Once Weekly for the Treatment of Obesity. New England Journal of Medicine, 387(3), 205-216.
2. National Institute for Health and Care Excellence. (2014). Gallstone disease: diagnosis and management. Clinical guideline CG188.
3. NHS Digital. (2023). Hospital Admitted Patient Care Activity 2022-23.
4. Stokes CS, et al. (2014). Gallstones: environment, lifestyle and genes. Digestive Diseases, 32(5), 538-548.
5. National Institute for Health and Care Excellence. (2024). Tirzepatide for managing overweight and obesity (TA1026).
6. Electronic Medicines Compendium. (2024). Mounjaro 2.5 mg solution for injection in pre-filled pen – Summary of Product Characteristics. Section 4.8: Adverse Reactions.