Changing physician prescribing habits through a cost-effective first generation cephalosporin formulary

Cephalosporin antibiotics account for a significant portion (approximately 10%) of our institution's drug budget. A 1985 survey demonstrated that 64% of our first generation injectable cephalosporin (FGIC) orders were for cefazolin. Of the cefazolin orders, approximately 77% used an "every 6 hour" dosage interval. It was thought that this dosage interval was associated with "physician habit" of prescribing similar agents "every 6 hours." By using an "every 8 hour" cefazolin dosage interval in most cases, significant cost savings in the hospital's drug budget could be realized. The Department of Pharmacy and the Pharmacy and Therapeutics (P&T) Committee developed and instituted an FGIC formulary procedure designed to promote the use of cefazolin with an "every 8 hour" dosing interval. Following presentation of literature guidelines to the P&T Committee, measurement of staff physician support through a written survey and presentation of extensive educational programs by the Department of Pharmacy, and FGIC formulary was implemented. The formulary policy included the automatic changing of every 6 hour cefazolin dosing intervals to every 8 hour intervals, with a physician option of "NO SUBSTITUTION." After implementation of the formulary policy, physician prescribing habits for FGIC's changed dramatically. Six months post-formulary, cefazolin accounted for 94% of FGIC prescriptions. Approximately 76% of cefazolin doses were being administered on an "every 8 hour" dosing interval as opposed to 21% prior to formulary implementation. Approximately $45,000 was saved during the first twelve months following formulary implementation. Physicians, pharmacists and nurses have supported the formulary policy.