Side Effects of Mounjaro (Tirzepatide)
The most common side effects of Mounjaro (tirzepatide) are gastrointestinal, with nausea (31%), diarrhea (23%), vomiting (12%), constipation (5%), and abdominal pain (5%) being the most frequently reported adverse effects. 1
Common Side Effects
Gastrointestinal Effects
- Nausea (31%)
- Diarrhea (23%)
- Vomiting (12%)
- Constipation (5%)
- Abdominal pain (5%)
- Decreased appetite
These gastrointestinal side effects are typically:
- Most pronounced during dose escalation
- Usually transient in nature
- Mild to moderate in severity
- Manageable with proper titration 2, 1
Strategies to Minimize Gastrointestinal Side Effects
- Start with the recommended low dose (2.5 mg weekly) and follow gradual titration schedule 1
- Reduce meal size
- Limit alcohol and carbonated drinks
- Avoid high-fat diets
- Consider antiemetics like ondansetron for nausea management
- Consider loperamide for diarrhea management 1
Rare but Serious Side Effects
Pancreatitis
Acute pancreatitis has been reported with tirzepatide use, similar to other GLP-1 receptor agonists 3. Patients should be monitored for:
- Severe abdominal pain
- Nausea and vomiting that doesn't resolve
- Elevated lipase levels
Appendicitis
Case reports suggest a potential association between tirzepatide and appendicitis, possibly due to changes in gastrointestinal motility and delayed gastric emptying 4.
Thyroid C-Cell Tumors
Tirzepatide carries a black box warning for the risk of thyroid C-cell tumors based on rodent studies, though human relevance is not determined 1. It is contraindicated in patients with:
- Personal or family history of medullary thyroid carcinoma
- Multiple endocrine neoplasia syndrome type 2
Other Potential Concerns
- Hypoglycemia (rare when used alone, more common when combined with insulin or sulfonylureas)
- Injection site reactions (occur in <1% of patients) 1
- Potential risk of cholelithiasis and cholecystitis
Special Population Considerations
- Not recommended during pregnancy or in women who may become pregnant
- No dose adjustment required for patients with renal impairment, including end-stage renal disease 1
Perioperative Considerations
For patients undergoing surgery:
- Consider stopping tirzepatide at least one week before elective procedures
- This minimizes the risk of aspiration due to delayed gastric emptying
- Consult with an anesthesiologist before any surgical procedure 1
Monitoring Recommendations
- Follow-up 4 weeks after initiation to assess:
- Side effect burden
- Weight loss progress
- Glycemic control (if used for diabetes)
- Consider dose reduction rather than discontinuation if benefits outweigh side effects 1
Tirzepatide offers significant therapeutic benefits for type 2 diabetes and obesity, but proper dose titration and patient education about potential side effects are essential to optimize treatment outcomes and patient comfort.