Anticoagulants

Drug choice follows a series of clinical gates, not a simple preference for the newest agent. First identify the indication: atrial-fibrillation stroke prevention and VTE treatment have different treatment pathways. In Canadian AF practice, CHADS-65 helps determine whether anticoagulation is indicated. Then look for conditions that override the usual DOAC preference, especially a mechanical heart valve or moderate-to-severe rheumatic mitral stenosis. For an otherwise eligible patient, a DOAC is usually easier to use because it acts quickly and does not require INR titration. That convenience does not eliminate monitoring: renal function, haemoglobin, weight, age, liver status, and interacting medicines can change whether the drug remains safe. Warfarin is slower and more demanding, but its effect can be measured and adjusted with INR, and it remains the correct choice in several high-risk situations. The practical question is therefore not which drug is universally best, but which anticoagulant fits this patient’s indication, physiology, and treatment constraints.