Bleeding events attributable to concurrent use of warfarin and other medications in high-risk elderly: meta-analysis and Italian population-based investigation.

More than half of bleeding events occurring among frail elderly using warfarin are attributable to a concomitant use of warfarin with certain drugs. Because some of these drugs appear to be essential for the treatment/prevention of cardiovascular conditions, and their concomitant use with warfarin could be acceptable in some cases, proper INR-monitoring and warfarin dose adjustments are requested.