Do Glucagon-like peptide-1 (GLP-1) receptor agonists need to be stopped before a colonoscopy in patients with diabetes?

GLP-1 Receptor Agonists and Colonoscopy: Management Recommendations

GLP-1 receptor agonists do NOT need to be stopped before colonoscopy for bowel preparation purposes, but they DO need to be stopped before colonoscopy if sedation/anesthesia will be used, due to aspiration risk from delayed gastric emptying.

Critical Distinction: Two Separate Issues

Issue 1: Bowel Preparation Quality

GLP-1 receptor agonists should NOT be discontinued solely for bowel preparation concerns 1, 2. The evidence shows:

• A 2025 meta-analysis found no significant difference in inadequate bowel preparation rates between GLP-1 RA users and controls (OR 1.00,95% CI 0.73-1.37) 2
• While one multicenter study showed higher rates of inadequate preparation in GLP-1 RA users (10% vs 4%), the clinical significance remains debatable given conflicting evidence 3
• The 2025 U.S. Multi-Society Task Force guidelines acknowledge that GLP-1 RAs delay gastric emptying but do not specifically recommend discontinuation for bowel preparation 1

The bowel preparation itself is generally adequate when GLP-1 RAs are continued 2.

Issue 2: Aspiration Risk During Sedation (The Real Concern)

This is where GLP-1 RAs must be stopped. The aspiration risk from delayed gastric emptying during sedation is well-established and requires medication discontinuation:

Recommended Holding Periods Before Colonoscopy with Sedation:

• Semaglutide (weekly): Hold for 3 weeks (three half-lives) before the procedure 4
• Tirzepatide (weekly): Hold for 3 weeks before the procedure 4
• Dulaglutide (weekly): Hold for 2-3 weeks before the procedure 4
• Liraglutide (daily): Hold for 3-4 days before the procedure 4

Critical evidence: Discontinuation for only 7 days is insufficient—studies show retained gastric contents persist even after 10-14 days of discontinuation 4. The ASA initially recommended 1 week for weekly agents, but emerging evidence demonstrates this is inadequate 4.

Clinical Decision Algorithm

For Colonoscopy WITHOUT Sedation (Unsedated Procedure):

• Continue GLP-1 RA without interruption 1, 2
• Use standard bowel preparation protocols 1
• No special precautions needed beyond standard preparation 2

For Colonoscopy WITH Sedation/Anesthesia:

Step 1: Determine medication and calculate holding period

• Weekly agents (semaglutide, tirzepatide, dulaglutide): 3 weeks 4
• Daily agents (liraglutide): 3-4 days 4

Step 2: Assess patient indication

• Non-diabetic patients (obesity/weight loss): Discontinue for full recommended period—risks outweigh benefits 4
• Diabetic patients: Consult endocrinology to weigh glycemic control risks against aspiration risk; may need bridging therapy 4

Step 3: If adequate holding period NOT achieved

• Consider postponing elective colonoscopy 4
• If proceeding, implement "full stomach precautions":
  • Point-of-care gastric ultrasound pre-procedure 4
  • Administer prokinetic drugs (metoclopramide or erythromycin) pre-operatively 4
  • Use rapid sequence intubation with full airway protection 4
  • Avoid supraglottic airways (case reports show aspiration with these devices) 4

Evidence Supporting Aspiration Risk

The mechanism is clear: GLP-1 RAs delay gastric emptying through multiple pathways 4:

• Inhibition of gastric peristalsis 4
• Increased pyloric tone 4
• Vagal nerve pathway activation 4

Documented clinical consequences:

• 24.2% of semaglutide users had residual gastric content vs 5.1% of controls, even after 12+ hour fasting 4
• Multiple case reports document pulmonary aspiration requiring ICU admission in patients who fasted 18-20 hours and stopped semaglutide only 4-6 days before procedures 4

Common Pitfalls to Avoid

1. Do not assume standard fasting guidelines are sufficient—retained gastric contents persist despite extended fasting in GLP-1 RA users 4

2. Do not rely on 1-week discontinuation for weekly agents—this is inadequate based on current evidence 4

3. Do not unnecessarily discontinue GLP-1 RAs for unsedated colonoscopy—the bowel preparation quality is not significantly impaired 2

4. Do not use supraglottic airway devices in patients who haven't had adequate medication discontinuation 4

Special Considerations

For patients with diabetes: The benefits of glycemic control may outweigh delayed gastric emptying issues in some cases, requiring individualized risk-benefit assessment with endocrinology consultation 4. However, for elective colonoscopy, the safer approach is adequate discontinuation with bridging therapy if needed 4.

Documentation requirements before procedure 4:

• Indication and dose of GLP-1 RA
• Date commenced and last dose taken
• Symptoms of nausea, vomiting, or abdominal distention
• Concomitant medications affecting gastric emptying (opioids, PPIs, tricyclic antidepressants)