Coumadin Tablet Strengths
No, Coumadin does not come in a 2.25 mg tablet formulation.
Available Tablet Strengths
According to the FDA-approved drug label, Coumadin (warfarin sodium) tablets are manufactured in the following specific strengths 1:
- 1 mg (pink tablet with D&C red no. 6 barium lake)
- 2 mg (lavender tablet)
- 2.5 mg (green tablet)
- 3 mg (tan tablet)
- 4 mg (blue tablet)
- 5 mg (peach tablet)
- 6 mg (teal tablet)
- 7.5 mg (yellow tablet)
- 10 mg (white, dye-free tablet)
Clinical Implications
If a dose of 2.25 mg is required, you must split tablets to achieve this dose. The most practical approach is to use:
- One 2 mg tablet plus one-quarter of a 1 mg tablet (2 + 0.25 = 2.25 mg), or
- Three-quarters of a 3 mg tablet (0.75 × 3 = 2.25 mg), or
- Alternate between 2 mg and 2.5 mg on different days to achieve an average weekly dose equivalent
Important Dosing Considerations
Warfarin dosing should be individualized based on INR monitoring, not predetermined tablet strengths. The American College of Cardiology recommends:
- Starting doses of 5 mg daily for most patients, or 2-4 mg daily in elderly patients 2, 3
- Dose adjustments based on INR values, typically altering the total weekly dose by 5-20% 4
- Target INR of 2.0-3.0 for most indications 2, 3
Elderly patients often require lower maintenance doses due to increased sensitivity to warfarin's anticoagulant effect 2, 5, which may necessitate unconventional doses like 2.25 mg achieved through tablet splitting.
Practical Pitfall
When splitting tablets or using combinations to achieve specific doses, ensure patients understand the regimen clearly to avoid dosing errors, as warfarin has a narrow therapeutic index where small changes can lead to significant INR fluctuations 4, 6.