High Protein - Low Carb

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Monday, August 1, 2005

PTINR.com Staff

Limited data but interesting observations of the Atkin's diet affect on warfarin.

An article in March 8 th Annals of Pharmacotherapy provided insight into high-protein, low carbohydrate diets and their impact on warfarin INR stability. The study of two patients called attention to high protein intake, warfarin (Coumadin ®) protein binding and the affects of stable INRs.

Significant increases in dosing were required to maintain the two case study patients in therapeutic range. Patient A required slightly more than 1.78 milligrams more per day while patient B required 1.6 milligrams additional per day both resulting in a likely prescription change and potential added expense.

Older patients aren't thought of as your typical Atkin's dieters but those patients who choose to increase their protein and cut-back on their carbohydrates may be altering their stable warfarin levels.

“High-protein diets have been shown to increase serum albumin levels. This may result in more warfarin binding to serum albumin, thereby decreasing the anticoagulant effect of warfarin. The increase of albumin occurs rapidly after initiation of a high-protein diet and appears to promptly affect anticoagulation therapy with warfarin.” Annals Pharmacotherapy 8 March 2005,

The Annals article cited only two cases but clinics now have an additional tool to query their patients when INR values drop for reasons other than prescription drugs. Patients' consistent increase of protein may be a worthwhile discussion for those presenting with sub-therapeutic INRs for no other apparent reason.