Therapeutic oral vitamin K antagonists (VKA) acenocoumarol, coumadin, coumarin, phenprocoumon, warfarin and the like. See also under the rodenticide/pesticides brodifacoum, diphacinone, diphenadione. See also under other anticoagulants heparin, thrombolytic agents, platelet glycoprotein aggregation inhibitors (anti-GPIIB/IIIA) (abciximab, ticlopidine, clopidogrel, eptifibatide) and direct (new) anti-IIa or anti-Xa oral anticoagulans (apixaban, dabigatran, rivaroxaban). Patients with pulmonary hypertension who receive oral anticoagulants are also at risk of hemorrhage in the chest and/or other organs. Drug abusers may surreptitiously take warfarin to prevent femoral vein thrombosis. Abused drugs and the smoke of certain cigarettes may contain coumarin or warfarin, causing coagulopathy (PMID 11547737, 17583404, 24275169). Antidotes and reversal agents: PMID 24275169, 26872887.