DOACs

Direct oral anticoagulants (DOACs) are a class of medicines that directly inhibit key components of the coagulation cascade to prevent clot formation. The main agents are dabigatran, a direct thrombin inhibitor, and rivaroxaban, apixaban, and edoxaban, which inhibit factor Xa. Some guidelines also recognize betrixaban for certain indications. DOACs are used as alternatives to warfarin for several indications.

DOACs are commonly prescribed for preventing stroke and systemic embolism in nonvalvular atrial fibrillation, and for the treatment of acute deep vein thrombosis (DVT) and pulmonary embolism (PE). They are also used for the prophylaxis of DVT after certain orthopedic procedures in some settings. Unlike warfarin, DOACs have fixed dosing and do not require routine coagulation monitoring in most patients.

Pharmacology and use: DOACs have rapid onset and relatively predictable effects, enabling fixed dosing with fewer dietary interactions. Renal function affects their clearance, so dosing and selection may depend on kidney function. They may interact with P-glycoprotein and, for some agents, with CYP3A4 inhibitors or inducers.

Safety and reversal: major adverse effects are bleeds, with intracranial bleeding risk often lower than warfarin but varying by agent and patient. Reversal strategies include idarucizumab for dabigatran and andexanet alfa for factor Xa inhibitors; supportive and non-specific measures may be used in bleeding. In pregnancy and certain valvular conditions (notably mechanical valves), DOACs are usually avoided in favor of other anticoagulants.

Special considerations: dosing adjustments are needed for renal impairment, hepatic disease, and advanced age. DOACs are not recommended for mechanical heart valves, and their use requires assessment of individual risk-benefit and comorbidities.