Which of the following is a common CYP17 inhibitor?

Aminoglutethimide is indeed recognized as a common CYP17 inhibitor. CYP17, or cytochrome P450 17A1, is an enzyme that plays a crucial role in the biosynthesis of androgens and estrogens, which are steroid hormones. By inhibiting CYP17, aminoglutethimide reduces the production of these hormones, which can be beneficial in treating certain hormone-sensitive cancers, such as breast cancer. This action is particularly useful in patients whose tumors are driven by estrogen or testosterone.

In contrast, other options do not primarily function as CYP17 inhibitors. Fulvestrant is an estrogen receptor antagonist used in treating hormone-receptor-positive breast cancer by blocking the effects of estrogen on cancer cells rather than inhibiting the CYP17 enzyme. Tamoxifen is aSelective Estrogen Receptor Modulator (SERM) that also blocks estrogen's effects in breast tissue but, similar to fulvestrant, does not specifically inhibit CYP17. Ketoconazole is an antifungal agent that has some off-label use as a hormone synthesis inhibitor, but it is not as commonly classified specifically as a CYP17 inhibitor and is more associated with CYP17 inhibition in the context of adrenal hormone suppression rather than its