When to stop subcutaneous (under the skin) Heparin (unfractionated heparin) before surgery?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: May 21, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

Subcutaneous heparin should be stopped 24 hours before surgery for therapeutic doses and 12 hours before surgery for prophylactic doses, as recommended by the American College of Chest Physicians evidence-based clinical practice guidelines 1. When considering the management of antithrombotic therapy in the perioperative period, it is crucial to balance the risk of thrombosis against the risk of bleeding. The guidelines suggest that for patients receiving bridging anticoagulation with therapeutic-dose subcutaneous low-molecular-weight heparin (LMWH), administering the last preoperative dose 24 hours before surgery is a reasonable approach to minimize bleeding risk while maintaining thromboprotection 1. Key considerations include:

  • The type of surgery and its associated bleeding risk
  • The patient's individual thrombotic risk factors, such as mechanical heart valves or recent venous thromboembolism
  • The specific type and dose of heparin being used
  • The need for a bridging strategy in high-risk patients After surgery, heparin can usually be resumed 24 hours postoperatively when adequate hemostasis is achieved, but this should be determined on a case-by-case basis in consultation with the surgical and anesthesia teams 1. In general, the decision to stop heparin should be individualized based on the patient's unique risk profile, and communication with the surgical team is essential to ensure optimal management.

From the Research

Stopping Subcutaneous Heparin Before Surgery

  • The decision to stop subcutaneous heparin before surgery depends on various factors, including the type of surgery, patient's risk of bleeding, and risk of venous thromboembolism (VTE) 2, 3.
  • There is no clear consensus on when to stop subcutaneous heparin before surgery, but it is generally recommended to discontinue it 6 to 12 hours before the procedure to minimize the risk of bleeding 4.
  • However, the optimal timing for stopping subcutaneous heparin may vary depending on the specific clinical situation and the patient's individual risk factors 5, 6.
  • It is essential to weigh the risks and benefits of continuing or discontinuing subcutaneous heparin before surgery, taking into account the patient's overall health status, the type of surgery, and the potential consequences of bleeding or VTE 2, 3.

Considerations for Stopping Subcutaneous Heparin

  • Patient's risk of bleeding: Patients with a high risk of bleeding may require earlier discontinuation of subcutaneous heparin to minimize the risk of perioperative bleeding 6.
  • Type of surgery: The type of surgery and the associated risk of bleeding may influence the decision to stop subcutaneous heparin before surgery 5, 4.
  • Patient's risk of VTE: Patients with a high risk of VTE may require continued thromboprophylaxis with subcutaneous heparin or alternative anticoagulants 2, 3.
  • Alternative anticoagulants: The use of alternative anticoagulants, such as fondaparinux or low-molecular-weight heparin, may be considered in patients who require continued thromboprophylaxis before surgery 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Full dose subcutaneous heparin therapy.

New York state journal of medicine, 1989

Research

A Retrospective Analysis of q12hr and q8hr Heparin for DVT/PE Prophylaxis in an Inpatient Rehabilitation Setting.

The Journal of pharmacy technology : jPT : official publication of the Association of Pharmacy Technicians, 2022

Research

Comparing fondaparinux and low molecular weight heparin for thromboprophylaxis after hip and knee arthroplasty: a systematic review and meta-analysis.

Blood coagulation & fibrinolysis : an international journal in haemostasis and thrombosis, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.