553f5c59_cyclopedia___Kaiser_Permanente_n_medicines_that_are_monitored_Tests_you_may_have
[Examples] Warfarin [What they do] It helps prevent blood clots. Because it prevents clots, it also helps prevent heart attacks, strokes, and other problems caused by blood clots. [Why monitor them] Things like an infection or a small change in your diet can change the way warfarin works. So can other medicines that you are taking. [How often] As often as your doctor suggests [Tests you may have] 
Prothrombin time (INR)
Health-Encyclopedia - Kaiser Permanente