ECONOMIC-IMPACT OF INTRAVENOUS-TO-ORAL ANTIBACTERIAL STEPDOWN THERAPY

Significant resources are required to bring anti-infectives to the mar ket, and these agents also represent a major expense to the consumer. In Canada, antiinfectives are the second largest source of patented dr ug revenue for the pharmaceutical industry, although their contributio n has declined over the past 3 years compared with cardiac and gastroi ntestinal drugs. Representing 20 to 30% of total drug costs, acquisiti on expenses for anti-infectives are also responsible for the single la rgest contribution to hospital drug expenditures, 70 to 80% of which c an be attributed specifically to antibacterials. Antibacterials can be administered by several routes. While oral treatment predominates in the ambulatory setting, both parenteral and oral routes of administrat ion are commonly used in the hospital. Parenteral administration is ty pically reserved for moderate to severe infections, while the oral rou te is usually utilised for the treatment of less serious infections. T he overuse of intravenous therapy was acknowledged decades ago and con cern still persists. Assessment of antiinfective utilisation patterns in the Vancouver Hospital and Health Sciences Centre in 1994 reveals t hat 1 of every 2 doses administered involved an intravenous dosage for mulation. However, oral dosage formulations were responsible for only one-tenth of the total acquisition costs for anti-infectives. The pref erential use of oral antibacterial dosage formulations can be associat ed with several therapeutic and economic benefits; it should permit mo re rapid patient mobilisation and earlier discharge, and potential int ravascular line-associated infections can be avoided. The acquisition costs for oral dosage formulations are approximately one-quarter of th ose for their injectable counterparts, while preparation and delivery are at least half as expensive. Intravenous-to-oral (IV-PO) stepdown t herapy typically follows one of 4 scenarios. Ideally, stepdown is acco mplished using the same drug with good oral bioavailability. Alternati vely, stepdown to a dissimilar agent with good bioavailability can be undertaken. Stepdown to the same agent with limited bioavailability sh ould be considered when patient and infection characteristics permit. Stepdown to a different agent with poor bioavailability is the least p referable scenario. In the published trials involving IV-PO stepdown t herapy, fluoroquinolones have been investigated more than any other an tibacterial class. Although there are no specific published reports in volving pefloxacin, this agent possesses some properties that suggest a potential role in stepdown therapy. If pefloxacin is prescribed for this purpose, clinicians will have to carefully apply stepdown criteri a and monitor therapy to ensure a successful conclusion to the treatme nt course.