MEDizzy - A 39-year-old man living in New Mexico was recently

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Antifungal Drugs

A 39-year-old man living in New Mexico was recently diagnosed with pulmonary coccidioidomycosis. A treatment was started with a drug that acts by inhibiting the fungal P-450 system. Which of the following drugs was most likely administered?

ExplanationCoccidioides immitis is sensitive to amphotericin B and antifungal azoles. Azole antifungals, primarily fluconazole and itraconazole, have replaced amphotericin B as initial therapy for most chronic pulmonary and disseminated infections. Amphotericin B is now usually reserved for patients with rapidly progressive coccidioidal infections. Azoles act by inhibiting the cytochrome P-450 system in fungal cells. The inhibition blocks the synthesis of ergosterol in the fungal cell membrane, leading to an antifungal effect . Relative selectivity occurs because the affinity for mammalian P-450 isozymes is less than that for the fungal isozymes. However, azoles can also block mammalian P-450 isozymes in the liver, which can explain the increased plasma concentration of many other drugs when co-administered with azoles.