Metronidazole cost containment: a two-stage intervention.

A two-stage intervention was undertaken to extend the dosing interval of metronidazole--from the typically prescribed q6h or q8h regimen to a q12h dosing interval. Following an 2-week informational period, all prescriptions for parenteral metronidazole specifying a dosage interval of 8 hours or less were modified to 12-hour dosage intervals, unless overridden by the prescriber. Prescriptions for the 6-month periods prior to and following the intervention were reviewed to assess its impact on prescribing patterns and cost containment. The incidence of regimens involving 12-hour intervals increased from 5 to 95% following the intervention. A 2-year general hospital/drug utilization health record screen found no drug substitution effect, nor any change in postoperative infection rate or death among metronidazole recipients. Overall, the two-stage intervention was a well-accepted and effective means of cost containment, resulting in an estimated yearly cost savings of $28,000.