Antibiotic cost reduction by providing cost information.

Antibiotic cost information was added to the computerized print-out for each patient of microbiology culture results, next to the antibiotic susceptibility list. During the first six months of this addition, the average monthly cost of antibiotics decreased by 16.5% ($7636) compared to the 12 months period preceding the study period. The average antibiotic cost per admission decreased by 15.7% ($1.61) and the average antibiotic cost/hospital day decreased by 10.6% ($0.23). Antibiotic savings were highest in the Department of Obstetrics and Gynaecology (21.7%) and lowest in the Department of Paediatrics (10.8%). Two-thirds of the average savings were initiated by the house-staff and the remainder by infectious disease consultants. The effect of this system on the level of medical care remains to be studied.