ITRACONAZOLE FOR EXPERIMENTAL PULMONARY ASPERGILLOSIS - COMPARISON WITH AMPHOTERICIN-B, INTERACTION WITH CYCLOSPORINE-A, AND CORRELATION BETWEEN THERAPEUTIC RESPONSE AND ITRACONAZOLE CONCENTRATIONS IN PLASMA ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Berenguer, J., Ali, N. M., Allende, M. C., Lee, J., Garrett, K., Battaglia, S., Piscitelli, S. C., Rinaldi, M. G., Pizzo, P. A., Walsh, T. J. 1994; 38 (6): 1303-1308

Abstract

Itraconazole and amphotericin B were compared by using a newly developed model of invasive pulmonary aspergillosis in rabbits immunosuppressed with methylprednisolone and cyclosporin A (CsA). Both itraconazole at 40 mg/kg (given orally) and amphotericin B at 1 mg/kg (given intravenously) had in vivo antifungal activity in comparison with controls. At these dosages, amphotericin B was more effective than itraconazole in reducing the tissue burden (log10 CFU per gram) of Aspergillus fumigatus (P < 0.05) and the number of pulmonary lesions (P < 0.01). However, there was considerable variation in the near-peak concentrations of itraconazole in plasma (median, 4.15 micrograms/ml; range, < 0.5 to 16.8 micrograms/ml) and a strong inverse correlation between concentrations of itraconazole in plasma and the tissue burden of A. fumigatus. An inhibitory sigmoid maximum-effect model predicted a significant pharmacodynamic relationship (r = 0.87, P < 0.001) between itraconazole concentrations in plasma and antifungal activity as a function of the tissue burden of A. fumigatus. This model demonstrated that levels in plasma of greater than 6 micrograms/ml were associated with a significantly greater antifungal effect. Levels in plasma of less than 6 micrograms/ml were associated with a rapid decline in the antifungal effect. Itraconazole, in comparison with amphotericin B, caused a twofold elevation of CsA levels (P < 0.01) but was less nephrotoxic (P < 0.01). This study of experimental pulmonary aspergillosis demonstrated that amphotericin B at 1 mg/kg/day was more active but more nephrotoxic than itraconazole at 40 mg/kg/day, that itraconazole increased concentrations of CsA in plasma, and that the antifungal activity of itraconazole strongly correlated with concentrations in plasma in an inhibitory sigmoid maximum-effect model. These findings further indicate the importance of monitoring concentrations of itraconazole in plasma as a guide to increasing dosage, improving bioavailability, and optimizing antifungal efficacy in the treatment of invasive pulmonary aspergillosis.

View details for Web of Science ID A1994NN77000015

View details for PubMedID 8092829