A 49-year-old woman with a prosthetic aortic valve presents with new-onset bruising. Her last international normalized ratio (INR) 6 weeks ago was 2.4. Today's INR is markedly higher, at 6.5.

She has not taken any extra warfarin. *This case is from Docplexus editorial team for educative purpose only Source: Warfarin and OTCs: An Unrecognized Risky Combination - Medscape - Jan 15, 2015.