warfarin

A blood thinner taken by mouth to prevent and treat clots, such as in atrial fibrillationatrial fibrillationAY-tree-ul fib-rih-LAY-shunAn irregular heart rhythm in which the upper chambers of the heart quiver instead of beating in an organized way.atri/o atrium (upper heart chamber)fibrill/o small fibers, quivering-ation processFull entry Close, deep vein thrombosisdeep vein thrombosisDEEP VAYN throm-BOH-sisA blood clot in a deep vein, most often in the leg or pelvis.thromb/o clot-osis conditionFull entry Close, pulmonary embolismpulmonary embolismPUL-muh-nair-ee EM-buh-liz-umA blockage of an artery in the lungs, usually by a blood clot that has traveled there from elsewhere in the body.pulmon/o lung-ary relating toembol/o plug-ism conditionFull entry Close and mechanical heart valves. It blocks the liver from using vitamin K to make clotting factors, so it takes several days to reach full effect. Its effect is followed with the INR blood test; the usual goal is 2 to 3, higher for some mechanical valves. Vitamin K reverses it.

Check the INR before doses and watch for bleeding (gums, nosebleeds, dark stools, blood in urine, big bruises). Teach the client to keep the amount of vitamin K foods (leafy greens) steady rather than avoid them, to tell every provider and dentist they take it, and to check before starting any new drug or herb, since many change its effect. Anticoagulants are on the ISMP high-alert list.