Side Effects of Wegovy (Semaglutide)
Wegovy (semaglutide) primarily causes gastrointestinal side effects including nausea, vomiting, diarrhea, constipation, and abdominal pain, which are typically transient and mild-to-moderate in severity. 1
Common Side Effects
Gastrointestinal Effects
- Nausea (most common)
- Vomiting
- Diarrhea
- Constipation
- Abdominal pain
- Esophageal reflux
- Flatulence
These gastrointestinal side effects typically occur during initiation and dose escalation periods and tend to diminish over time with continued use.
Other Common Side Effects
- Injection site reactions
- Elevated heart rate
- Hypoglycemia (particularly in patients with diabetes)
- Headache
- Fatigue
- Dizziness
Serious Safety Concerns
Black Box Warning
- Risk of thyroid C-cell tumors in rodents (human relevance not determined) 1
Other Serious Concerns
- Pancreatitis: Has been reported in clinical trials, though causality not established. Discontinue if pancreatitis is suspected 1
- Acute kidney injury: Use caution in patients with kidney disease when initiating or increasing dose 1
- Gallbladder disorders: Including cholelithiasis and gallstone-related complications 1
- Hypoglycemia: Particularly when used with insulin or insulin secretagogues 1
Special Precautions
Contraindications
- Pregnancy and breastfeeding: All weight management medications including Wegovy are contraindicated in women who are or may become pregnant 1
- Personal or family history of medullary thyroid carcinoma
- Multiple endocrine neoplasia syndrome type 2
Monitoring Recommendations
- Assess efficacy and safety at least monthly for the first 3 months and at least quarterly thereafter 1
- Consider discontinuing if less than 5% weight loss after 3 months of use 1
- Monitor for signs of pancreatitis (severe abdominal pain, persistent nausea/vomiting)
- Monitor for dehydration due to gastrointestinal side effects
Managing Side Effects
Strategies to Reduce GI Side Effects
- Start with lower doses and titrate slowly
- Reduce meal size
- Limit alcohol and carbonated beverages
- Avoid high-fat diets
- Consider antiemetics for significant nausea
- Use loperamide for troublesome diarrhea
Dosing Considerations
Wegovy is administered as a once-weekly subcutaneous injection with a recommended dose escalation schedule:
- 0.25 mg once weekly for 4 weeks
- 0.5 mg once weekly for 4 weeks
- 1 mg once weekly for 4 weeks
- 1.7 mg once weekly for 4 weeks
- Maintenance dose of 2.4 mg once weekly
This gradual dose escalation helps minimize gastrointestinal side effects.
Clinical Pearls
- Early responders (>5% weight loss in first 3 months) typically have better long-term outcomes 1
- Discontinuation results in regain of 50-67% of weight loss within 1 year, suggesting the need for long-term therapy
- Women of reproductive potential must use reliable contraception methods during treatment
Wegovy has demonstrated significant weight loss benefits (approximately 15% of body weight) and cardiovascular benefits, which must be weighed against the side effect profile when considering this medication for weight management.