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Therapeutics · Cardiovascular

Anticoagulation in atrial fibrillation

Therapeutic goals

  • Prevent stroke in patients whose risk justifies anticoagulation
  • Choose the agent the patient can actually take, correctly, for years
  • Keep bleeding risk managed, not merely feared

Patient factors that steer the choice

  • Stroke risk score versus bleeding risk (modifiable factors first)
  • Mechanical valve or moderate-severe mitral stenosis (warfarin territory)
  • Renal function (DOAC dosing and eligibility)
  • Adherence reality: INR clinics impose structure DOACs quietly remove
  • Interacting drugs: inducers, NSAIDs, antiplatelets

Major drug classes

Anticoagulants

Treatment approach

  1. 01Decide anticoagulation at all

    Risk scores inform, judgment decides; aspirin is not a soft alternative. It under-protects and still bleeds.

  2. 02DOAC first for most

    Non-valvular AF defaults to a DOAC; warfarin keeps mechanical valves, significant mitral stenosis, and severe renal failure (per jurisdiction).

  3. 03Dose precisely

    Apixaban's reduction criteria are strict (2 of 3); real-world under-dosing 'to be safe' delivers strokes, not safety.

  4. 04Make bleeding survivable

    Address modifiables (NSAIDs, alcohol, uncontrolled BP, falls hazards); plan for procedures; know the reversal landscape.

Monitoring

  • Warfarin: INR and time-in-range
  • DOAC: renal function at least annually, adherence at every refill
  • Everyone: bleeding symptoms, new medications, OTC NSAID audit

Pearls

  • The refill record is the DOAC's INR: gaps in dispensing are unprotected days.
  • An anticoagulated patient buying naproxen is the pharmacy's most preventable hemorrhage.

Choose the drug

Anticoagulation in atrial fibrillation

74-year-old, new non-valvular AF. Stroke risk clearly indicates anticoagulation.

Weight 58 kg, creatinine 128 µmol/L, age ≥ 74. On ibuprofen PRN for knees.

Best anticoagulation plan?

Keep going

Apixaban →Warfarin →DOAC + inducers →Warfarin counselling →

Last reviewed 2026-08-15 · Principle-level content; jurisdiction-specific recommendations live in the cited guidelines: 2023 ACC/AHA/ACCP/HRS Guideline for the Management of Atrial Fibrillation · CCS Atrial Fibrillation Guidelines (current)