Warfarin Dose Adjustment Calculator
Guides warfarin dose adjustment based on current INR versus target INR range. Commonly used in ICU and inpatient settings for warfarin bridging and management.
Score interpretation
INR below target range. Patient at risk of thromboembolic events.
→ Increase weekly dose by 10-20%. Recheck INR in 3-7 days. Consider LMWH bridging if high thromboembolic risk (mechanical valve, recent VTE). Assess for reduced adherence or drug interaction.
INR within therapeutic range. Continue current dose.
→ No dose change required. Recheck INR in 4-8 weeks if stable. Weekly if recently adjusted.
INR mildly above range. Increased bleeding risk.
→ Reduce weekly dose by 10-15%. Omit 1 dose if INR > 3.5. Recheck INR in 3-7 days. Counsel on bleeding symptoms.
INR dangerously elevated. High bleeding risk.
→ Hold warfarin. If INR > 5 with bleeding: Vitamin K 1-5 mg PO or IV. If INR > 8 or serious bleeding: PCC (Beriplex/Octaplex) + Vitamin K 5-10 mg IV. Haematology advice.
Interpretation bands for the Warfarin Dose. Apply clinical judgement and local guidance.
References
- Keeling D, et al. Guidelines on oral anticoagulation with warfarin, 4th edition. Br J Haematol. 2011;154(3):311-324.
- Ansell J, et al. The pharmacology and management of the vitamin K antagonists. Chest. 2008;133(6 Suppl):160S-198S.
Related
Curated clinical cross-links plus same-class fallbacks.
- ATRIA Bleeding Risk Score · Anticoagulation
- DOAC Score for Selecting Direct Oral Anticoagulant in Non-Valvular AF · Anticoagulation
- ORBIT Bleeding Risk Score for Anticoagulation in AF Patients · Anticoagulation
- Heparin Infusion Dose Calculator · Anticoagulation
- Paediatric INR Goals for Mechanical Heart Valves · Anticoagulation
- Dopamine (ICU — Vasopressor/Inotrope) · Catecholamine (Dose-Dependent Vasopressor/Inotrope)
- Hydroxocobalamin (High-Dose — Cyanide Antidote) · Cyanide Antidote (Vitamin B12 Precursor at High Dose)
- Dopamine hydrochloride · Inotrope / vasopressor (dose-dependent)
- Warfarin · Anticoagulant
- Bivalirudin (PCI Anticoagulation) · Direct Thrombin Inhibitor / PCI
- Enalapril with hydrochlorothiazide · ACE inhibitor + thiazide diuretic (fixed-dose)
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.