Deep vein thrombosis (DVT) is a condition characterized by the presence of thrombus lodged in a deep vein in the body. The most common sites are the thigh and calf. One of the serious sequelae of DVT is pulmonary embolism that is made by a small part of the thrombus that gets detached and migrates until it gets trapped in the pulmonary vasculature causing pulmonary infarction. The drug of choice for DVT is heparin to stop the thrombus from migrating and to prevent new thrombus formation. The nurse must be aware that the antidote for heparin toxicity or overdose, which can present as excessive bleeding, is protamine sulfate. Vitamin K counteracts the effects of warfarin. Narcan (naloxone) counteracts the effects of opioids. Digibind counteracts the effects of digoxin.