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Vitamin K supplementation to decrease variability of International Normalized Ratio in patients on vitamin K
1Department of Pharmacy, University of North Carolina Hospitals, USA.
Current Opinion in Hematology
|August 13, 2008
Summary
Daily vitamin K supplementation may stabilize International Normalized Ratios (INRs) in patients with unstable INRs, potentially reducing thrombosis and bleeding risks. Further research is needed to confirm these findings in larger patient groups.
Area of Science:
- Pharmacology
- Cardiology
- Internal Medicine
Background:
- Unstable International Normalized Ratios (INRs) in patients on vitamin K antagonists increase risks of thrombosis and bleeding.
- Dietary vitamin K intake fluctuations are a known cause of INR variability.
Purpose of the Study:
- To investigate if daily vitamin K supplementation can decrease INR variability in patients with unstable INRs.
- To assess the impact of stable vitamin K intake on INR stability.
Main Methods:
- Review of four studies (one retrospective, three prospective) examining vitamin K supplementation effects on INR variability.
- Analysis of studies using varying daily doses of vitamin K1 (100–500 μg).
Main Results:
- One retrospective and two prospective studies suggest vitamin K1 supplementation may stabilize INRs in patients with a history of instability, though individual responses vary.
- One prospective study found no significant difference in time in therapeutic range with daily 100 μg vitamin K1 compared to placebo.
Conclusions:
- Vitamin K supplementation shows potential for decreasing INR variability in patients with unstable INRs.
- Larger population studies are required to definitively establish the efficacy of vitamin K supplementation for INR stability.
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