Table 7.
Specific low-dose regimen for initiating warfarin therapy for patients > 70 years65
| Day | INR value 10 AM | Warfarin dose (mg) 6 PM |
|---|---|---|
| Day 0 | Do not measure | 4 |
| Day 1 | Do not measure | 4 |
| Day 2 | Do not measure | 4 |
| Predicted maintenance dose | ||
| Day 3 | <1.3 | 5 |
| INR ≥ 1.3 | 4 | |
| INR ≥ 1.5 | 3 | |
| INR ≥ 1.7 | 2 | |
| INR ≥ 1.9 | 1 | |
| INR ≥ 2.5 | Measure INR daily and omit doses until INR < 2.5 mg, then give 1 mg |
Notes: This algorithm does not apply to patients who have received warfarin within the preceding week of have a pretreatment international normalized ratio (INR) >1.3.