Failure of ketoconazole in two patients with blastomycosis.

Two patients with severe pulmonary blastomycosis were treated with ketoconazole. One patient developed disseminated disease while receiving this drug. After responding to incomplete treatment with amphotericin B, this patient relapsed while continuing ketoconazole therapy. The second patient failed to respond to ketoconazole and died shortly after treatment with amphotericin B was instituted. We conclude that it is dangerous to use ketoconazole as initial treatment in patients with severe forms of blastomycosis. Death, relapse, and prolonged morbidity may be the result. In such cases, amphotericin B is still the drug of first choice despite its toxicity, inconvenience, and expense of administration.