When should a patient with type 2 diabetes and impaired renal function, taking GLP-1 (Glucagon-like peptide-1) agonists for weight loss, stop their medication before undergoing general anaesthetic and thyroid surgery?

When to Stop GLP-1 Agonists Before General Anesthesia and Thyroid Surgery

For patients taking GLP-1 agonists for weight loss (non-diabetic indication), discontinue weekly formulations like semaglutide for at least 3 weeks before elective thyroid surgery requiring general anesthesia. 1

Recommended Holding Periods by Formulation

Weekly GLP-1 Agonists (Semaglutide, Dulaglutide)

• Stop 3 weeks (21 days) before surgery to allow clearance of approximately three half-lives 1
• The American Society of Anesthesiologists' initial recommendation of 1 week is insufficient—discontinuation for only 7 days does not decrease the prevalence of retained gastric contents 1
• This 3-week period applies to both injectable and oral semaglutide formulations 1

Daily GLP-1 Agonists (Liraglutide)

• Stop 3-4 days before surgery 1

Critical Distinction: Weight Loss vs. Diabetes Indication

For non-diabetic patients using GLP-1 agonists for weight loss, the risks of continuing until shortly before surgery outweigh any benefits—hold the medication for the full 3 weeks without exception. 1

For diabetic patients, consult with the treating endocrinologist to weigh glycemic control risks against aspiration risk, and discuss bridging diabetic therapy if the medication must be held longer than the next scheduled dose 1. However, given your patient has impaired renal function and type 2 diabetes, the renal protective benefits of GLP-1 agonists 2 must be balanced against the immediate surgical risk.

Why This Extended Period Matters

Mechanism of Aspiration Risk

• GLP-1 agonists significantly delay gastric emptying through inhibition of gastric peristalsis and increased pyloric tone, mediated through vagal pathways 1
• 24.2% of patients on semaglutide had residual gastric content compared to 5.1% of controls, even after 12+ hour fasting periods and 10-14 days of medication discontinuation 1
• Multiple case reports document pulmonary aspiration requiring ICU admission in patients who fasted 18-20 hours and stopped semaglutide only 4-6 days before surgery 1

Evidence Against Shorter Holding Periods

• Studies demonstrate that holding weekly GLP-1 agonists for only 1 week before surgery is inadequate 1
• Patients with only 8 days between last dose and surgery should be considered at high risk for retained gastric contents 1

If Adequate Holding Period Cannot Be Achieved

Consider Postponement First

• Postpone and reschedule the elective thyroid surgery to allow adequate medication clearance 1
• Use shared decision-making to openly discuss risks and benefits of proceeding 1

Risk Mitigation Strategies if Surgery Must Proceed

• Perform point-of-care gastric ultrasound pre-operatively to assess for residual gastric contents (target gastric volume <1.5 ml/kg) 1
• Administer prokinetic drugs such as metoclopramide or erythromycin pre-operatively 1
• Implement rapid-sequence intubation with full airway protection—avoid supraglottic airways, as case reports show aspiration with these devices 1
• Treat as a "full stomach" case with appropriate precautions 1, 3
• Consider pre-emptive gastric decompression in very high-risk patients 1

Special Considerations for Your Patient

Renal Impairment

• No dose adjustment is required for semaglutide, dulaglutide, or liraglutide across all stages of chronic kidney disease 4
• GLP-1 agonists reduce albuminuria and slow eGFR decline, providing renal protective benefits 2
• The 3-week holding period remains the same regardless of renal function 1

Type 2 Diabetes Management During Holding Period

• Consult endocrinology regarding bridging therapy to maintain glycemic control during the 3-week medication-free period 1
• Monitor blood glucose closely, especially if the patient was well-controlled on the GLP-1 agonist 5
• Consider temporary alternative glucose-lowering medications that do not delay gastric emptying 1

Pre-Operative Documentation Requirements

Document the following in the pre-operative assessment 1:

• Indication and dose of GLP-1 receptor agonist
• Date drug commenced and any dose variations
• Last dose taken (verify 3 weeks have elapsed for weekly formulations)
• Presence of nausea, vomiting, or abdominal distention symptoms
• Co-prescribed drugs that delay gastric emptying (opioids, proton pump inhibitors, tricyclic antidepressants)
• Recent recreational drug use that delays gastric emptying (alcohol, cannabis)

Common Pitfalls to Avoid

• Do not rely on standard fasting guidelines alone—retained gastric contents persist despite extended fasting in patients on GLP-1 agonists 1
• Do not assume one week of discontinuation is adequate—emerging evidence demonstrates this is insufficient to eliminate aspiration risk 1
• Do not use supraglottic airway devices if the medication has not been held for adequate duration—case reports document aspiration events with these devices 1
• Do not proceed with elective surgery if gastrointestinal symptoms are present on the day of the procedure 3

High-Risk Scenarios Requiring Extra Caution

• Patients who recently started GLP-1 agonists or increased their dose may require even longer discontinuation periods 1
• Patients with pre-existing digestive symptoms show significantly higher rates of gastric retention and require more than 21 days discontinuation 1
• Patients experiencing nausea, vomiting, or abdominal distention should have procedures postponed until symptoms resolve 1