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INR elevation associated with diarrhea in a patient receiving warfarin
J K Smith1, A Aljazairi, S H Fuller
1Salem Veterans Affairs Medical Center, WA, USA.
The Annals of Pharmacotherapy
|April 14, 1999
Summary
Acute diarrhea can elevate international normalized ratio (INR) in warfarin patients, potentially causing bleeding. Frequent INR monitoring and warfarin dose adjustments are crucial during diarrheal episodes, especially with reduced oral intake.
Area of Science:
- Pharmacology
- Gastroenterology
Background:
- Warfarin is a common anticoagulant medication.
- Maintaining a therapeutic international normalized ratio (INR) is critical for patients on warfarin therapy, particularly those with mechanical heart valves.
Observation:
- A case report details a patient on warfarin experiencing recurrent international normalized ratio (INR) elevations coinciding with episodes of acute diarrhea.
- These INR elevations occurred without changes in warfarin dosage, new medications, or signs of infection, suggesting an alternative cause.
Findings:
- The study observed a direct correlation between the duration of diarrheal episodes and the degree of INR elevation.
- Reduced oral intake during diarrhea may lead to decreased vitamin K absorption, a key factor in warfarin metabolism.
Implications:
- Diarrhea, especially with decreased oral intake, can significantly impact warfarin therapy and increase bleeding risk.
- Clinicians should consider frequent INR monitoring and warfarin dose adjustments in patients experiencing diarrhea to prevent supratherapeutic INRs and potential hemorrhage.