What are the concerns with using anesthesia in patients taking Glucagon-like peptide-1 (GLP-1) receptor agonist medications?

Anesthesia Concerns with GLP-1 Medications

The primary concern with GLP-1 medications and anesthesia is the increased risk of pulmonary aspiration due to delayed gastric emptying, which can result in retained gastric contents despite adherence to standard fasting guidelines. 1

The Core Problem: Delayed Gastric Emptying

GLP-1 receptor agonists mechanistically slow gastric emptying, which is confirmed by the European Medicines Agency Pharmacovigilance Risk Assessment Committee. 2 This pharmacologic effect creates a clinical dilemma where patients may have full stomachs even after prolonged fasting periods. 1

Multiple case reports document aspiration events in patients who fasted 18-20 hours—far exceeding standard guidelines—yet still regurgitated during anesthesia induction. 1, 2 One study reported an odds ratio of 10.23 (95% CI: 2.94-35.82) for pulmonary aspiration in patients taking GLP-1 receptor agonists undergoing elective surgery. 2

Conflicting Guideline Recommendations

There is significant divergence in expert recommendations, reflecting the limited evidence base:

2024 Guidance (Earlier Approach)

• Hold GLP-1 receptor agonists for at least three half-lives before procedures (approximately 88% drug clearance) 1
• For weight loss patients: mandatory three half-life hold 1
• For diabetes patients: consult endocrinology regarding risks/benefits of holding 1

2025 Consensus (Most Recent)

The 2025 multidisciplinary UK consensus from the Association of Anaesthetists and multiple specialty societies recommends patients should CONTINUE taking GLP-1 receptor agonists throughout the perioperative period. 1 This represents a major shift from earlier recommendations.

Evidence-Based Risk Stratification Approach

Given the conflicting guidelines, use this algorithmic approach prioritizing the most recent 2025 consensus:

Pre-Procedure Assessment

• Discuss aspiration risk and mitigation strategies using shared decision-making 1
• Do NOT use gastrointestinal symptoms alone to determine gastric content—symptoms are unreliable predictors 1
• Identify high-risk features: recent medication initiation, dose escalation, ongoing nausea/vomiting/abdominal distention 1

Fasting Protocol

• Adhere to standard fasting guidelines (not prolonged fasting) 1
• Consider 24-hour clear fluid diet followed by standard 6-hour fasting for enhanced safety 3

Day of Procedure Risk Assessment

Use point-of-care gastric ultrasound to directly visualize gastric contents before induction 1, 2

• Gastric volume < 1.5 mL/kg suggests lower aspiration risk 1, 2
• If significant gastric contents present, proceed to aspiration risk mitigation strategies 1

Aspiration Risk Mitigation Strategies

For patients with elevated gastric contents or high-risk features:

1. Consider regional anesthesia as primary technique when appropriate 1
2. Administer prokinetic drugs (metoclopramide or erythromycin) preoperatively 1
3. Use modified rapid sequence intubation with tracheal tube (with or without cricoid pressure per local practice) 1, 2
4. Head-up position for induction 1
5. Consider pre-emptive gastric decompression in very high-risk patients 1
6. Awake tracheal extubation 1

Secondary Concerns Beyond Aspiration

Glycemic Control Issues

Stopping GLP-1 receptor agonists creates risk of perioperative hyperglycemia, which is independently associated with increased hospital length of stay, surgical site infections, acute kidney injury, and critical care admissions. 1 This harm from stopping the medication must be weighed against aspiration risk—hence the 2025 recommendation to continue therapy. 1

Patients using GLP-1 receptor agonists for obesity (without diabetes) are at risk for stress hyperglycemia and require regular capillary glucose monitoring with prompt intervention. 1

FDA Drug Label Warning

The FDA label for liraglutide explicitly warns that it "delays gastric emptying" and notes "rare postmarketing reports of pulmonary aspiration in patients receiving GLP-1 receptor agonists undergoing elective surgeries." 4 The FDA states that available data are insufficient to inform specific recommendations about modifying fasting or temporarily discontinuing the medication. 4 Patients must be instructed to inform healthcare providers prior to planned surgeries if taking GLP-1 receptor agonists. 4

Critical Pitfalls to Avoid

• Do not assume prolonged fasting (>20 hours) provides safety—case reports prove otherwise 1, 2, 5
• Do not rely on absence of GI symptoms to rule out retained gastric contents 1
• Do not automatically hold medications for three half-lives without considering the 2025 consensus recommendation to continue therapy 1
• Do not forget to monitor glucose in patients using GLP-1 receptor agonists for weight loss, as they lack diabetes diagnosis but remain at risk for stress hyperglycemia 1