Prospective Evaluation of Risk Factors for Antibiotic‐Associated Bleeding in Critically III Patients

A prospective surveillance program was initiated to determine the relative role of antibiotics containing N‐methylthiotetrazole (NMTT) versus patient risk factors in producing antibiotic‐associated bleeding. Five hundred forty‐six critically ill patients with serum albumin 30 g/L or below were evaluated for evidence of a bleeding event as documented by clinical observation, hemoglobin changes, and transfusions. Bleeding events occurred in 16% of patients receiving an aminoglycoside combination, 10% receiving antibiotics with the NMTT side chain, and 14.5% receiving antibiotics not containing NMTT (p>0.05). The bleeding rate was highest in febrile patients with cancer (14.5%) and lowest in those with a suspected or documented abdominal infection (10%) (p=0.04), but within each patient group there was no difference among the antibiotics. We conclude that the use of NMTT‐containing antibiotics is not an independent risk factor for bleeding, but the role of severity of illness may be underappreciated. 1992 Pharmacotherapy Publications Inc.