What medications should be taken or avoided before a colonoscopy?

Medication Management Before Colonoscopy

For patients undergoing colonoscopy, antiplatelet and anticoagulant medications should be managed according to procedure risk and patient thrombotic risk, with most medications requiring temporary discontinuation before high-risk procedures like polypectomy. 1

Medication Categories and Timing

Bowel Preparation Medications

• Take bowel preparation as prescribed using the "Split-Dose" method (preferred):
  • First dose: Evening before colonoscopy (5:00-9:00 PM)
  • Second dose: Morning of colonoscopy (approximately 5 hours before procedure)
  • Consume only clear liquids from the start of preparation until after colonoscopy 2
  • Do not take oral medications within 1 hour before or after starting bowel preparation 2

Antiplatelet Medications

Low-Risk Procedures (diagnostic colonoscopy with biopsy)

• Continue all antiplatelet medications including aspirin, clopidogrel, prasugrel, and ticagrelor 1

High-Risk Procedures (polypectomy, EMR, ESD)

• Low thrombotic risk patients:

  • Stop P2Y12 receptor antagonists (clopidogrel, prasugrel, ticagrelor) 7 days before procedure 1
  • Continue aspirin if already prescribed 1
  • Restart P2Y12 receptor antagonists 1-2 days after procedure 1

• High thrombotic risk patients (recent coronary stents, etc.):

  • Continue aspirin 1
  • Consult with cardiologist about P2Y12 receptor antagonists 1
  • Consider temporary cessation only if:

    • 6-12 months after drug-eluting coronary stent

    • 1 month after bare metal coronary stent 1

Anticoagulant Medications

Warfarin

• Low-risk procedures: Continue warfarin, ensure INR within therapeutic range 1
• High-risk procedures with low thrombotic risk:
  • Stop warfarin 5 days before procedure
  • Check INR prior to procedure (ensure <1.5)
  • Restart warfarin evening of procedure with usual daily dose
  • Check INR one week later 1
• High-risk procedures with high thrombotic risk:
  • Stop warfarin 5 days before procedure
  • Start LMWH 2 days after stopping warfarin
  • Administer last dose of LMWH at least 24 hours before procedure
  • Check INR before procedure (ensure <1.5)
  • Restart warfarin evening of procedure
  • Resume LMWH day after procedure until adequate INR achieved 1

Direct Oral Anticoagulants (DOACs)

• Low-risk procedures: Omit morning dose on day of procedure 1
• High-risk procedures:
  • Take last dose 3 days before procedure 1
  • For dabigatran with CrCl 30-50 mL/min, take last dose 5 days before procedure 1
  • Consult hematologist for patients with rapidly deteriorating renal function 1
  • Resume DOACs 2-3 days after procedure depending on bleeding and thrombotic risks 1

Other Medications

• If taking tetracycline, fluoroquinolone antibiotics, iron, digoxin, chlorpromazine, or penicillamine:
  • Take these medications at least 2 hours before and not less than 6 hours after bowel preparation 2
• Most other routine medications can be taken with a small sip of water on the day of procedure

Special Considerations

High Bleeding Risk Factors

• Polyp size >1 cm
• Use of pure cutting current during polypectomy
• Multiple polyps
• Advanced age
• Comorbidities (renal failure, liver disease, heart failure) 1

High Thrombotic Risk Conditions

• Prosthetic metal heart valve in mitral position
• Atrial fibrillation with mitral stenosis
• Recent stroke/TIA within 3 months
• Recent VTE while on anticoagulation 1

Post-Procedure Management

• If antiplatelet or anticoagulant therapy was discontinued, resume up to 2-3 days after procedure based on bleeding and thrombotic risks 1
• Advise patients on antiplatelets or anticoagulants of increased risk of post-procedure bleeding 1

Common Pitfalls to Avoid

1. Unnecessary discontinuation of aspirin - Evidence shows aspirin can safely be continued for most endoscopic procedures, including polypectomy 1, 3
2. Failure to bridge high-risk patients - Patients with mechanical heart valves require LMWH bridging when warfarin is stopped 1
3. Inappropriate timing of DOAC discontinuation - DOACs have shorter half-lives than warfarin but still require adequate time for clearance before high-risk procedures 1
4. Neglecting renal function - Patients with impaired renal function require longer DOAC discontinuation periods, especially for dabigatran 1
5. Resuming anticoagulation too early - After high-risk procedures, anticoagulation should be resumed after adequate hemostasis is achieved 1

The management of medications before colonoscopy requires balancing the risks of bleeding against thrombotic complications. Following these evidence-based guidelines helps minimize both risks while ensuring effective colonoscopy preparation.