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Phytonadione I.V. Beats S.C. at Lowering INR

Katherine M. Bennett

A small study published in the Dec. 13/27, 1999 Archives of Internal Medicine showed that, in patients receiving warfarin therapy, high International Normalized Ratios (INRs) can be corrected faster by giving an intravenous (i.v.) rather than subcutaneous (s.c.) injection of phytonadione.

Researchers evaluated the effect of phytonadione 1 mg administered i.v. or s.c. to 22 patients with an INR greater than 6 but with no symptoms of bleeding. Eight hours after the injection, patients who received the i.v. dose had a significantly greater decrease in INR than did the patients in the other group. Although s.c. injection of phytonadione was effective, its action was not as quick as with the i.v. dose.