The misconceptions about warfarin.
Oral anticoagulants, especially warfarin, are one of the most frequently prescribed drugs worldwide. Several guidelines and expert recommendations have been published to guide the practising physicians in appropriate prescription of these agents. Despite being one of the most effective medications, several misconceptions exist about their use which has no evidence basis. This article aims to dispel five such myths.

Bleeding is one of the commonest adverse effects observed in patients who are prescribed warfarin. However, haemorrhagic complications do not develop in majority of patients on warfarin, despite prolonged usage. The contribution from any anticoagulant drug to ‘bleeding’ is the ‘prolongation’ of bleeding, being inhibitors of coagulation factors, rather than ‘causation’ of bleeding. For example, an international normalized ratio (INR) of 3 to 4 means that an individual is likely to bleed 3 to 4 times more than someone who is not on warfarin, but only after bleeding has commenced due to a different cause. For the same reason, when an individual who is on any anticoagulant medication including warfarin develops bleeding, it is imperative that a cause of bleeding is identified (arrange gastrointestinal endoscopy, cystoscopy, etc.).1 In this context, anticoagulant-related bleeding or warfarin-related bleeding maybe a better terminology for general use to avoid this commonly held misconception.

The role of anti-platelet agents, non-steroidal anti-inflammatory drugs and cyclo-oxygenase-2 inhibitors in worsening warfarin-related bleeding needs emphasis. …