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Article
September 28, 1957

ORALLY ADMINISTERED PHYTONADIONE IN BISHYDROXYCOUMARIN-INDUCED HYPOPROTHROMBINEMIA

JAMA. 1957;165(4):330-333. doi:10.1001/jama.1957.02980220014004
Abstract

Oil-soluble phytonadione (vitamin K1) is the most effective antidote to every known coumarin and indandione derivative. While a dose of 10 mg. given orally is as effective as 100 mg. by vein over an eight-hour observation period, the physician must not be lulled into feeling confident that normal clotting mechanism has been produced. Despite the observed potency of phytonadione, the irregularity of the response to the drug, either orally or intravenously administered, is puzzling. Determinations of prothrombin time must be repeated at frequent intervals, and phytonadione should be readministered if a reversal of prothrombin time is not obtained. When such circumstances do occur, whole blood transfusions are indicated.

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