Plasma concentration of itraconazole and its antifungal prophylactic efficacy in patients with neutropenia after chemotherapy for acute leukemia

Abstract: Patients with acute leukemia are at high risk of fungal infection, suggesting that a preventive strategy is required. Fourteen patients receiving intensive chemotherapy for acute leukemia were studied to evaluate antifungal prophylaxis using itraconazole, and the plasma concentration of the drug was measured to determine its relationship to clinical efficacy. The median age of the patients was 50 years (range, 25 to 79 years), and all patients had neutropenia (less than 500 neutrophils/μl) which had lasted a median of 16 days (range, 4 to 30 days). Itraconazole was given orally at a dose of 200 mg (four capsules of 50 mg) once daily for at least 14 days. An H2-receptor antagonist was also given to prevent chemotherapy-induced gastrointestinal toxicity. Trough plasma concentrations of itraconazole and its metabolite, hydroxyitraconazole, were determined by reverse-phase high-performance liquid chromatography. The mean concentrations of itraconazole and hydroxyitraconazole on day 10 were 300 ± 96 ng/ml (range, 131–428 ng/ml) and 776 ± 369 ng/ml (range, 320–1582 ng/ml), respectively. There were marked inter-patient variations in both concentrations. No side effects were observed in the patients, and there was no definite fungal infection episode during this study. Daily oral administration of 200 mg of itraconazole appears to be effective as prophylaxis against fungal infection in neutropenic patients with acute leukemia. However, there were marked individual variations in the itraconazole plasma concentrations, which suggests that the plasma concentration should be monitored in patients with a risk of low absorption of this drug to adjust the dose given to an adequate level.