GLP-1 Receptor Agonist Discontinuation Before Anesthesia

For elective surgery requiring anesthesia, discontinue weekly GLP-1 receptor agonists (semaglutide, tirzepatide, dulaglutide) for 3 weeks (21 days) and daily formulations (liraglutide) for 3–4 days before the procedure to minimize pulmonary aspiration risk from delayed gastric emptying. 1, 2

Evidence-Based Holding Periods by Formulation

Weekly Formulations

Semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound): Hold for 3 weeks before elective surgery, as the half-life is approximately 7 days and three half-lives (≈88% drug clearance) are required to minimize aspiration risk. 1, 2
Dulaglutide (Trulicity): Hold for 2–3 weeks before surgery, with a half-life of 4.5–4.7 days. 1, 2

Daily Formulations

Liraglutide (Victoza, Saxenda): Hold for 3–4 days before surgery, with a half-life of approximately 13 hours. 1, 2

Oral Semaglutide (Rybelsus)

Oral semaglutide: Hold for 3 weeks (21 days) before elective procedures, as the half-life remains approximately one week regardless of administration route. 2

Why the American Society of Anesthesiologists' Original Recommendation Is Inadequate

The ASA initially recommended holding weekly GLP-1 receptor agonists for only 1 week before elective surgery, but emerging evidence demonstrates this is insufficient—discontinuation for 7 days did not decrease the prevalence of retained gastric contents. 1, 2
Gastric ultrasonography studies reveal that 24.2% of patients on semaglutide have residual gastric content versus 5.1% of controls, even after 12+ hour fasting periods and 10–14 days of medication discontinuation. 1, 2
Multiple case reports document pulmonary aspiration requiring ICU admission in patients who fasted 18–20 hours but stopped semaglutide only 4–6 days before surgery. 1, 2

Mechanism of Aspiration Risk

GLP-1 receptor agonists delay gastric emptying by inhibiting gastric peristalsis and increasing pyloric tone via vagal pathways, creating a persistent "full stomach" risk even with appropriate preoperative fasting. 1, 2
This delayed gastric emptying is documented even with long-acting formulations like semaglutide using scintigraphy, showing persistent effects despite some tachyphylaxis development. 3
The delayed gastric-emptying effect persists for 10–14 days after drug discontinuation, raising peri-operative aspiration risk independent of appetite-suppression effects. 3

Critical Distinction: Diabetes vs. Weight-Loss Indication

For Weight-Loss Patients (Non-Diabetic)

Hold medication for the full 3 weeks without exception, as the risks of continuing until shortly before surgery outweigh any benefits in patients using GLP-1 receptor agonists for weight management. 1, 2

For Diabetic Patients

Consult with the treating endocrinologist to weigh the risks and benefits of holding the drug for at least three half-lives, as prolonged cessation may have detrimental effects on perioperative glycemic control. 1, 2
The benefits of glycemic control in the perioperative period may outweigh the issues related to delayed gastric emptying in diabetic patients, requiring individualized risk-benefit assessment. 2
Consider bridging therapy (e.g., insulin or oral hypoglycemics) if the GLP-1 agent must be held longer than the next scheduled dose. 2

Risk Mitigation When Adequate Holding Period Not Achieved

If the medication has not been stopped for adequate duration, implement the following strategies:

Consider postponement and rescheduling of the procedure to allow adequate medication clearance. 1, 2
Perform point-of-care gastric ultrasound pre-operatively to assess for residual gastric contents (target gastric volume <1.5 ml/kg). 1, 2
Administer prokinetic drugs such as metoclopramide or erythromycin pre-operatively to enhance gastric emptying. 1, 2
Implement rapid-sequence intubation with full airway protection rather than supraglottic airways, as case reports show aspiration with supraglottic devices. 1, 2
Treat the case as a "full stomach" scenario and apply standard aspiration-precaution measures (elevated head-of-bed, cuffed endotracheal tube). 2
Consider pre-emptive gastric decompression (nasogastric tube) in patients judged to be at very high aspiration risk. 2

High-Risk Scenarios Requiring Extra Caution

Recent initiation or dose escalation of a GLP-1 agonist—patients who have recently started semaglutide or increased their dose are at higher risk and may require even longer discontinuation periods. 2
Presence of nausea, vomiting, or abdominal distention—procedures should be postponed until symptoms resolve. 2
Concurrent use of other gastric-emptying-delaying medications (opioids, proton pump inhibitors, tricyclic antidepressants). 2
Recent intake of recreational substances that slow gastric motility (alcohol, cannabis). 2
Patients with pre-existing digestive symptoms show significantly higher rates of gastric retention and require more than 21 days discontinuation. 1

Preoperative Documentation Requirements

Document the following in the preoperative assessment:

Indication and dose of GLP-1 receptor agonist. 1, 2
Date drug commenced, dose variations, and last dose taken. 1, 2
Symptoms of nausea, vomiting, or abdominal distention. 1, 2
Co-prescribed drugs that can delay gastric emptying (opioids, proton pump inhibitors, tricyclic antidepressants). 2
Recent intake of recreational drugs that delay gastric emptying (alcohol, cannabis). 2

Common Pitfalls to Avoid

Do not rely on standard fasting guidelines alone, as they are insufficient for patients on GLP-1 receptor agonists—retained gastric contents persist despite extended fasting. 2
Do not assume that one week of discontinuation is adequate, as emerging evidence demonstrates this is insufficient to eliminate aspiration risk. 1, 2
Avoid using supraglottic airway devices in patients who have not had adequate medication discontinuation, as case reports document aspiration events with these devices. 1, 2
Recognize that approximately 88% of the drug is cleared after three half-lives, but there is no strong evidence that gastric emptying fully normalizes after this time, so continued vigilance is required. 2

Guideline Limitations and Ongoing Vigilance

Standard pre-operative fasting guidelines alone are insufficient for patients on GLP-1 receptor agonists; retained gastric contents can persist despite extended fasting. 2
Although ≈88% of the drug is cleared after three half-lives, robust evidence that gastric emptying fully normalizes at that point is lacking; continued aspiration vigilance is advised. 2
The risk of aspiration during general anesthesia is unknown, but caution is advised in patients who recently commenced on GLP-1 receptor agonists. 4

How many days before anesthesia should GLP‑1 receptor agonists be discontinued, specifying differences for daily versus weekly formulations?

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