A 77-year-old woman who developed a 2-fold increase in INR while receiving APAP with concomitant acenocoumarol (8), and a 74-year-old man experienced a 3-fold increase in INR when APAP was added to his stable
warfarin regimen (6). Fluindione has also been implicated in this
interaction (9). In a prospective, randomized, double-blind, placebo-controlled trial 36 patients received either APAP 2 g daily, 4 g daily, or placebo for 4 weeks.