Hypoprothrombinemia in Patients With Cancer Receiving Cefoperazone and Mezlocillin

• Forty-one patients with cancer who were receiving cefoperazone sodium plus mezlocillin sodium were prospectively followed up for the development of abnormal bleeding or hypoprothrombinemia. Ten of 41 patients developed an increased prothrombin time, three with a hemorrhagic episode. Serum transport proteins and serum carotene were measured in 18 patients, six of whom developed hypoprothrombinemia. Low serum prealbumin and low serum carotene levels were associated with the development of hypoprothrombinemia. Patients with cancer are especially predisposed to the development of antibiotic-associated hypoprothrombinemia. This is probably a result of protein-calorie malnutrition and low vitamin K stores.