Effect of aminoglycoside-use restrictions on drug cost.

The effect on drug costs of restricting aminoglycoside use in a teaching hospital is described. In October 1980, the pharmacy and therapeutics committee deleted tobramycin from the formulary because of its high cost and relative lack of therapeutic advantages compared with gentamicin. Amikacin use was restricted. Concurrently, physicians were instructed in the proper use and dosage of gentamicin via lectures and dosing nomograms provided by the clinical pharmacist. Chart reviews of patients receiving gentamicin showed that the incidence of nephrotoxicity (defined by an increase in serum creatinine of 0.5 mg/dl) was 0%, 4.5%, and 6.5% in fiscal years 1981, 1982, and 1983, respectively. Based on the percentage of total aminoglycoside use represented by tobramycin, gentamicin, and amikacin during the year before implementation of the policy, projected cost savings for three years was more than $42,000. Expensive and improper aminoglycoside use should be a prime target for reduced spending as budgetary constraints in hospitals increase.