Itraconazole Serum Trough Concentrations Using Oral Capsules for the Treatment of Chronic Pulmonary Aspergillosis: What is the Target?

Background In regions where there is only itraconazole capsule as a therapeutic option for treatment of chronic pulmonary aspergillosis (CPA), measuring the serum concentrations becomes even more important for therapeutic success. Objective Evaluate the initial itraconazole serum trough concentrations after the administration of oral capsule of itraconazole for the treatment of CPA. Methods The measurement was performed at least 7-days after initiation of therapy. The standard treatment at our institution was a 200 mg capsule every 12 h. We defined that an adequate serum trough concentration of itraconazole during treatment was 1–4 mg/L. Results This study recruited 28 patients. The median value was 0.30 mg/L (IQR 0.01–0.70). Only 11% (n = 3) had adequate serum concentrations based on guideline recommendation. All patients with clinical deterioration had itraconazole serum levels ≤ 0.8 mg/L. Conclusion The initial serum concentrations of itraconazole after capsule formulation administration were low. Increasing the dose should be considered when the itraconazole concentration is low, especially if it is ≤ 0.8 mg/L, and the patient presents with clinical deterioration. Larger studies are needed to evaluate the adequate concentrations recommended for CPA.