Interaction between paracetamol and warfarin in patients: a double-blind, placebo-controlled, randomized study.

Abstract

The most plausible hypothesis to explain the in vivo interaction is that paracetamol (or its metabolites) interfere with enzymes involved in vitamin K-dependent coagulation factor synthesis. Paracetamol at 4 g daily (a dose higher than that used in clinical practice) potentiates the anticoagulant response produced by warfarin. Clinicians should be aware of this clinically significant and underestimated interaction.