Warfarin remains the most commonly prescribed anticoagulant in Australia but like all anticoagulants, its use is associated with an increased risk of bleeding.

The Australasian Society of Thrombosis and Haemostasis (ASTH) recently updated consensus guidelines for warfarin reversal to reflect latest evidence and the clinical experience of a panel of author-practitioners.

These guidelines offer advice on strategies to prevent over-anticoagulation. They also address the principles of warfarin reversal in acute care and provide recommendations on bridging (substituting) anticoagulation therapy in different clinical settings.

These strategies are especially important:

• when warfarin therapy is complicated by bleeding
• when the INR is above target but with no evidence of bleeding
• in patients on warfarin therapy who require invasive procedures.

Warfarin best practice — ways you can help

Minimise bleeding risk in patients starting warfarin:

• Avoid high initial warfarin loading doses; a 5mg starting dose is generally preferable and an even lower starting dose may be appropriate for older people, who are generally more sensitive to warfarin. A slow loading course is safe for people with AF and achieves an INR of 2–3 in 3–4 weeks for most.

Replace medicines that interact with warfarin when possible:

• avoid concomitant use of NSAIDs and certain antibiotics with warfarin
• avoid concomitant antiplatelet therapy except when clinical benefit is known, such as with mechanical heart valves, acute coronary syndrome or recent coronary stents.

Discuss the key points of warfarin management with the patient:

• Ensure patients understand the importance of dosing and monitoring; provide educational materials on dietary, alcohol and drug (including complementary, alternative and over-the-counter medicines) interactions that influence INR.
• Refer to the 2013 ASTH guidelines for recommendations related to anticoagulant bridging and perioperative care.

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Source: ‘How to manage warfarin bleeds – updated recommendations’ (2013) NPS Direct, 18 April