Pharmacist interventions to improve prescribing of vancomycin and tobramycin

The effect of clinical pharmacist interventions that promoted the use of nafcillin rather than vancomycin and of gentamicin rather than tobramycin, when appropriate, was evaluated. Physician information sheets and criteria describing appropriate use of the target drugs vancomycin and tobramycin were developed by a clinical pharmacist and infectious disease physicians. When drugs were prescribed for indications that did not meet the established criteria, the clinical pharmacist either contacted the prescribing physician or left the sheet in the patient's chart if the physician was not available. The average use of the target drugs and their alternatives was evaluated monthly during two six-month study periods and compared with the average use of these drugs during a three-month period before the target-drug programs were initiated. Throughout the 12-month study, on a per-patient basis, nafcillin use increased 31% while vancomycin use decreased 27% compared with the reference period; gentamicin use increased 21% while tobramycin use decreased 12% during the same period. These changes in use resulted in a net decrease in drug expenditures of $161,396. Approximately 0.5 full-time equivalent was spent on the program, and the return on investment for the service was greater than 10 to 1. Clinical pharmacist interventions through target-drug programs were effective in improving the appropriateness of vancomycin and tobramycin prescribing based on literature-derived criteria. The effects achieved by these interventions may decrease with time, and ongoing drug-use monitoring and physician education are necessary.