GGC Medicines - Table 4 - Management of patients undergoing procedures with high risk of bleeding in the pre-operative period on warfarin

Table 4: Management of patients on warfarin undergoing procedures with a high risk of bleeding in the pre-operative period.

For prescribing information on prophylactic and therapeutic doses of Low Molecular Weight Heparin (LMWH) referred to in this table, see here.

Pre-operative anticoagulation Day -5 (5 days before procedure)
Low risk of thrombosis	High risk of thrombosis	Extremely high risk of thrombosis
Stop warfarin (i.e. omit 5 doses prior to procedure). No pre-op low molecular weight heparin (LMWH) is required.	Stop warfarin (i.e. omit 5 doses prior to procedure). Organise the prescription and administration of therapeutic dose LMWH for days -3, -2 and -1 in the morning.¹ (The final dose to be administered in the morning the day before surgery)	Stop warfarin (i.e. omit 5 doses prior to procedure). Organise the prescription and administration of therapeutic dose enoxaparin 1mg/kg TWICE DAILY for days -3, -2 and -1 for 5 doses.¹ Do not exceed single dose of 150mg. (The final dose to be administered in the morning the day before surgery)
Pre-operative anticoagulation Day -3 and -2
Low risk of thrombosis	High risk of thrombosis	Extremely high risk of thrombosis
No pre-op LMWH is required. In the unplanned / acute setting, warfarin may be withheld pending a procedure. In this case, prophylactic dose LMWH would be appropriate when INR<2.	Therapeutic dose LMWH in the morning between 8am and 10am.	Therapeutic dose enoxaparin 1mg/kg TWICE DAILY.
Pre-operative anticoagulation Day -1
Low risk of thrombosis	High risk of thrombosis	Extremely high risk of thrombosis
No pre-op LMWH is required. Check INR. In the unplanned / acute setting, warfarin may be withheld pending a procedure. In this case, prophylactic dose LMWH would be appropriate when INR<2.	Therapeutic dose LMWH in the morning between 8am and 10am. If dose cannot be administered before 10am it should be omitted. Check INR.	Therapeutic dose enoxaparin 1mg/kg to be taken in the morning between 8am and 10am. If dose cannot be administered before 10am it should be omitted. Check INR.
Day of procedure
Low risk of thrombosis	High risk of thrombosis	Extremely high risk of thrombosis
Ideally, patient should not be 1st on the operating list - this allows time for a day zero INR to be obtained prior to surgery if required. Recheck INR at 8am if not already ≤1.4 on day -1. Target INR for procedure is ≤1.4. If INR>1.4 administer vitamin K (phytomenadione) IV 1mg as a single dose² and repeat INR.

Notes

LMWH should be prescribed and issued from secondary care, and the patient instructed on self-administration. [Ideally organised through Same Day Admission Unit]. The aim is for patients, or carers, to self-administer LMWH at home, however liaison with district nurse services may be required. Please ensure patients are given a sharps bin to safely dispose of LMWH syringes.
Use an insulin syringe to draw up 0.1 ml of phytomenadione 10mg/1ml before adding to 100ml glucose 5% bag and administering over 15-30 minutes.

Guideline reviewed: August 2025

Page updated: July 2026