Investigation of the clinical efficacy and dosage of intravenous ciprofloxacin in patients with respiratory infection

Abstract

Purpose. Multidrug-resistant Pseudo- monas aeruginosa (MDRP), which seems to be linked to antibiotics consumption, has become a significant problem. Infection control is of vital importance, hence, proper use of antimicrobial drugs is one of the most crucial roles of hospital pharmacists. In this study, we surveyed patients who had been prescribed intravenous (i.v.) ciprofloxacin (CPFX) as the only antibiotic, and evaluated the relation between the antimicrobial activity of CPFX and pharmacokinetic /pharmacodynamic from the blood concentration of CPFX. Methods. This study was performed retrospectively to 112 adult patients diagnosed as having respiratory infections who had been treated as inpatients with intravenous CPFX for more than 3 days at Toho University Omori Hospital in Tokyo. Minimum inhibitory concentration (MIC) for the bacterium was obtained from the antimicrobial susceptibility testing performed according to the guidelines. The potential efficacy of CPFX was evaluated by the peak plasma concentration (Cmax), area under the concentration curve (AUC) and AUC/MIC. The predictive AUC of each patient was obtained from the modified formulae reported by Forrest et al. (1993) [1]. Results. Although CPFX is excreted from the kidney, standard treatment with this drug does not take renal function into consideration. Our results indicated that CPFX was effective in less than 50% of the patients who received it. Moreover, the AUC/MIC ratio in both the responder group and the non-responder group was less than 125 that is the clinical target ratio of CPFX for gram-negative bacteria. Conclusion. These results suggest that the clinical use of CPFX for the treatment of infectious diseases does not reach the target AUC/MIC ratio, and that the concentration of CPFX is not within the range to which many pathogens are susceptible in a large proportion of patients. To ensure the effective treatment of patients with infectious diseases and to prevent the development of resistance in bacteria, we recommend therapeutic drug monitoring (TDM) of CPFX in hospitals.