Itraconazole is an imidazole derivative that is effective against many clinically important fungal infections, including aspergillosis, candidiasis, cryptococcosis, and histoplasmosis [1]. We report a case of thrombocytopenia and leukopenia associated with the long-term use of itraconazole.

A 54-year-old man presented with acute myelogenous leukemia, FAB M4. He was treated with polychemotherapy (6-thioguanine, ara-C, and daunorubicin [TAD] and hexamethylmelamine, adriamycin, and melphalan [HAM]) [2] and achieved complete remission after the first cycle of TAD. Two weeks after receiving HAM, the patient developed fever, and a chest radiograph showed infiltrates suggestive of fungal infection. The patient's clinical condition and radiographic results improved after treatment with amphotericin B and 5-flucytosine. Before the patient was discharged, antifungal therapy was changed to itraconazole (200 mg/d). The patient was also being treated with enalapril, piretanide, and ranitidine.

A decrease in the patient's platelet count was first noted when he had been receiving itraconazole for 6 weeks. The platelet count decreased progressively from 98 to 33 cells/nL. His leukocyte count decreased from 9.8 to 3.6 cells/nL, and the neutrophil count decreased from 4.1 to 2.2 cells/nL. Bone marrow biopsy results showed a clear reduction in the number of megakaryocytes. Results of erythropoiesis and granulopoiesis were normal. No evidence of acute myelogenous leukemia was found. Treatment with itraconazole, enalapril, piretanide, and ranitidine was discontinued. When enalapril, piretanide, and ranitidine were reintroduced after the platelet count increased, the recovery of the platelet and leukocyte counts was not effected.

Although thrombocytopenia has been reported as a rare side effect of treatment with fluconazole (another imidazole derivative) [3], this is the first report of thrombocytopenia and leukopenia associated with itraconazole. Because of its broad antifungal spectrum, itraconazole is frequently prescribed. It is therefore important for clinicians to be aware of these possible side effects, particularly in patients with cancer, because thrombocytopenia and leukopenia might otherwise mistakenly be attributed to relapse of malignant disease.