Technique for calculation of the true costs of antibiotic therapy.

An in-house method for costing antibiotic therapy is presented which quantifies hidden costs including costs arising from intravenous administration, labour, serum antibiotic assay, monitoring of haematological and biochemical indices and disposal of sharp instruments. A study of various hospital procedures relating directly to antibiotic therapy was undertaken in an acute medical ward, which involved determination of staff members performing various procedures, consumables used and time taken. Results of this study facilitated accurate quantification of hidden costs of i.v. antibiotic therapy in this ward. Using these results, the cost of five-day courses of gentamicin, cefuroxime, penicillin G, flucloxacillin and erythromycin were calculated. The costing of adverse effects was not attempted. It is recommended that a costing technique of this sort is used in cost-benefit analysis of antibiotic use, as the cost of the drug alone is misleading.