Antibiotic therapeutic interchange program: six years of experience.

To assess the long-term impact of a therapeutic interchange program on the use of target antimicrobial drugs, we conducted a retrospective study of target drug utilization at our institution--a 1,000-bed Canadian tertiary care teaching hospital. Data were assessed to determine target drug utilization, incidence of therapeutic interchanges, and patient-target drug exposures. Results showed that the incidence of therapeutic interchanges per patient-target drug exposure decreased from a mean of 23% to 2%, resulting in a total net savings for the target drugs of approximately $1.07 million (Canadian) over 6 years. Prescriber acceptance and low manpower requirements combine to make this a useful method of altering prescribing patterns and reducing drug and drug delivery costs.