Unexpected vitamin K deficiency in hospitalized patients.

Twenty-seven patients developed vitamin K deficiency unexpectedly in the postoperative period or during hospitalization for a variety of medical conditions. Twenty-two of the patients were on antibiiotics. Nineteen were on no oral intake during part of their hospital stay, and the remainder had a poor food intake. Fifty percent developed vitamin K deficiency within seven days. It is suggested that the rapid onset of vitamin K deficiency in these patients may have been due to a combination of the use of multiple antibiotics and poor food intake.