Anticoagulants

Anticoagulants

• Warfarin

• DOACs: apixaban, rivaroxaban, edoxaban, dabigatran

• Heparin

  • Heparin infusion

  • Low molecular weight heparin: enoxaparin, dalteparin

• Everything else

  • Fondaparinux

  • Bivalirudin

Warfarin

Original and most trusted anticoagulant

• Mechanism of action: anti vitamin k, inhibiting factor 2, 7, 9, 10

• Takes 72hrs to become effective, including a prothrombotic initial phase

• Therefore requires bridging, usually with enoxaparin

• Monitoring: frequent INR to ensure therapeutic

  • INR: 2-3- majority of indications

  • INR 2.5-3.5: metallic valves

• Reversal agents [see Gram Project's diagram below]

  • Vitamin K- slow reversal

  • Prothrombin complex- quick reversal (FFP can be used too if nil prothrombin)

Indications

• Antiphospholipid Syndrome (APS) 

• Mechanical Heart Valve

• VTE treatment & secondary prevention: DVT & Pulmonary Embolus 

DOACs

DOAC: direct oral anticoagulants

Examples: apixaban, dabigatran, edoxaban, edoxaban

Indications: 

• VTE treatment and prophylaxis- DVT & Pulmonary Embolus 

• Atrial fibrillation stroke prevention

Monitoring: nil monitoring required & fewer interactions

Reversal agents

• Idarucizumab: dabigatran

• Andexanet alfa: apixaban & rivaroxaban

Comments

DOACs use has been increasing due to the equivalent efficacy to warfarin with fewer montioring requirements. 

The reversal agents are rarely required. 

Heparin

Types: heparin infusion, low molecular heparin (enoxaparin, dalteparin)

Fondaparinux

Mechanism of action: factor Xa inhibitor

Main indication: NSTEMI acute management & Heparin induced thrombocytopenia

Bivalirudin

Mechanism of action: direct thrombin inhibitor

Indication: Heparin induced thrombocytopenia

References and Resources

1. British Committee for Standards in Haematology (BCSH) guidelines https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2141.2011.08753.x

2. GramProject: https://gramproject.com/ . https://gramproject.com/diagram/management-of-high-inr-in-warfarin-use/ 

Page written in 2024.