Itraconazole therapy for blastomycosis and histoplasmosis. NIAID Mycoses Study Group

To assess the efficacy and toxicity of orally administered itraconazole in the treatment of nonmeningeal, nonlife-threatening forms of blastomycosis and histoplasmosis.

Prospective, nonrandomized, open trial.

Multicenter trial at 14 university referral centers.

Eighty-five patients with culture or histopathologic evidence of blastomycosis (48 patients) or histoplasmosis (37 patients). Patients receiving other systemic antifungal therapy were excluded.

Itraconazole was administered orally at doses of 200 to 400 mg/d. Patients in whom treatment was considered a success were treated for a median duration of 6.2 months (blastomycosis) and 9.0 months (histoplasmosis). Disease activity was assessed at baseline; drug efficacy and toxicity were evaluated at monthly intervals during therapy, and efficacy was evaluated at regular follow-up visits after completion of therapy. The median duration of posttreatment evaluation for successfully treated patients was 11.9 months (blastomycosis) and 12.1 months (histoplasmosis).

Among the 48 patients with blastomycosis, success was documented in 43 (90%). The success rate for patients treated for more than 2 months was 95% (38 of 40). Among the 37 patients with histoplasmosis, success was documented in 30 (81%). The success rate for patients treated for more than 2 months was 86% (30 of 35). All patients with histoplasmosis in whom treatment failed had chronic cavitary pulmonary disease. Toxicity was minor; only 25 (29%) patients experienced any side effects, and itraconazole toxicity necessitated stopping therapy in only 1 patient.

Itraconazole is a highly effective therapy for nonmeningeal, nonlife-threatening blastomycosis and histoplasmosis. The drug is associated with minimal toxicity.