Anticoagulation During Bowel Preparation
Anticoagulation therapy can generally be continued safely during bowel preparation for colonoscopy, as bowel preparation itself is not considered a high-risk procedure for bleeding complications. 1
Risk Assessment Framework
Low-Risk Procedures
- Diagnostic endoscopy (including colonoscopy without polypectomy)
- Mucosal biopsies
- ERCP without sphincterotomy
- Diagnostic balloon-assisted enteroscopy
- Endosonography without tissue sampling
High-Risk Procedures
- Polypectomy (especially >1cm)
- Endoscopic mucosal resection
- Endoscopic sphincterotomy
- Therapeutic balloon-assisted enteroscopy
- Dilation of strictures
Management of Anticoagulants During Bowel Preparation
Warfarin
- For low-risk procedures: Continue warfarin therapy 1
- Ensure INR does not exceed therapeutic range in the week before procedure
- For high-risk procedures: Consider temporary interruption based on thrombotic risk
Direct Oral Anticoagulants (DOACs)
- For low-risk procedures: Omit morning dose on day of procedure 1
- For high-risk procedures: Last dose should be taken ≥48 hours before procedure 1
- For patients on dabigatran with reduced renal function (CrCl 30-50 mL/min): Last dose should be taken 72 hours before procedure 1
Antiplatelet Agents
- For low-risk procedures: Continue aspirin and P2Y12 receptor antagonists (e.g., clopidogrel) 1
- For high-risk procedures in low thrombotic risk patients: Continue aspirin but discontinue P2Y12 receptor antagonists five days before procedure 1
- For high-risk procedures in high thrombotic risk patients: Continue aspirin and consult with a cardiologist regarding P2Y12 receptor antagonists 1
Special Considerations
Bowel Preparation Specifics
- Oral colonic purgative solutions have been associated with cardiac arrhythmias in some patients 1
- Sodium phosphate preparations can cause electrolyte abnormalities and should be avoided in patients with underlying cardiovascular and renal disease 1
- Polyethylene glycol solutions are generally safer for patients with cardiovascular disease 1
Post-Polypectomy Management
- If polypectomy is performed, antiplatelet therapy can typically be resumed when oral intake is allowed 2
- For high thrombotic risk patients, prioritize early resumption (same day) 2
- For high bleeding risk situations (large polyps >1cm), consider delaying resumption by 24-48 hours if thrombotic risk is low 2
Common Pitfalls and Caveats
Failure to distinguish between bowel preparation and the endoscopic procedure itself: The bowel preparation itself is low-risk, but the planned endoscopic procedure may be high-risk and require anticoagulation adjustment.
Dehydration risk: Ensure adequate hydration during bowel preparation to minimize risk of thrombotic events, especially in patients whose anticoagulants have been temporarily interrupted.
Electrolyte disturbances: Monitor for electrolyte abnormalities, particularly with sodium phosphate preparations, which could increase arrhythmia risk in patients with cardiovascular disease.
Assuming all colonoscopies are low-risk: Since polyps are encountered in 22.5-34.2% of diagnostic colonoscopies, some endoscopists choose to manage all colonoscopies as high-risk procedures with respect to anticoagulation management 1.
Bridging therapy risks: Recent evidence suggests heparin bridging therapy during warfarin cessation may increase bleeding risk without significant benefit in many patients 3.
By following these guidelines, clinicians can safely manage anticoagulation during bowel preparation while minimizing both bleeding and thrombotic risks.