Medications that interfere with the effect of warfarin

This is a partial list of medications that may increase or decrease warfarin effect on the INR. The patient's medications should be analyzed closely for drug interactions with warfarin, especially when initiating or altering therapy. The effect of a drug interaction can be unpredictable; thus, individuals receiving interacting medications are likely to require increased INR monitoring. Additional medications may increase bleeding risk independent of (or in addition to) effects on the INR (eg, NSAIDs, antiplatelet medications). Refer to UpToDate for additional details. Drug interactions may be evaluated using the Lexi-interact program included with UpToDate.