CYP17A1 and Adrenal insufficiency: Moreover, the antifungal agent ketoconazole, which is used as an inhibitor of the activities of several enzymes involved in androgen synthesis such as CYP17 and CYP11, has been investigated.6 However, ketoconazole lacks specificity for the CYP17 family of enzymes, which unfortunately leads to significant toxicities (eg, hepatotoxicity, gastrointestinal toxicity, and adrenal insufficiency).6