Dosage formulation and the efficacy of the oral to IV switch are important drug characteristics in implementing an effective therapeutic interchange. Because clinical stability is a major indicator for switching from IV to oral medication, the use of optimized dosing strategies with antimicrobials can result in earlier IV-to-oral switching and subsequent hospital discharge, leading to cost savings.

The requirement for dosage adjustments when patients are in transition between IV and oral routes of administration with can affect the risk of medical errors and clinical outcomes. In addition, because of its PK profile, ciprofloxacin must be administered twice or three times daily; by contrast, respiratory fluoroquinolones are given just once daily. This requirement increases the possibility of missed doses.

Optimized dosing strategies with antimicrobial agents, such as the use of higher doses with fluoroquinolones, can result in more rapid and complete eradication of the causative pathogen. However, not all quinolones have a therapeutic index that allows for the administration of a higher dose. Clinical studies with the 750-mg dose of have established its safety and efficacy; symptoms were resolved in a greater proportion of patients receiving 750 mg by the third day of therapy, compared with patients receiving 500 mg in the treatment of community-acquired pneumonia, including severely ill patients.


Although therapeutic interchange can be an important strategy in reducing drug-acquisition costs in hospital pharmacies, an overarching review of all hospital areas affected and overall direct and indirect costs must be considered before such a program is implemented. The impact of a switch on the dynamics and workload of the hospital staff must be analyzed, particularly when a formulary change might alter dosing regimens or further complicate therapeutic decisions. When a therapeutic interchange with the fluoroquinolones is being considered, it must be decided whether a single fluoroquinolone or dual fluoroquinolones (canadian ciprofloxacin plus a respiratory) will be used to ensure full coverage of indications.

In addition to efficacy and safety, the PK profile, the spectrum of coverage, and resistance patterns of the drug to be substituted must be given high priority, particularly when overall cost differences are minimal. Further research is needed to fully assess the cost advantages of each strategy in various hospital settings.