Abiraterone acetate (trade name Zytiga) is a prodrug to the abiraterone, steroidal compound with antiandrogen activity and a 17 α-hydroxylase/C17,20-lyase (CYP17) inhibitor. It is indicated in combination with prednisone for the treatment of patients with metastatic castration-resistant prostate cancer. Abiraterone acetate is converted in vivo to abiraterone which inhibits CYP17, enzyme expressed in testicular, adrenal, and prostatic tumor tissues and required for androgen biosynthesis. Administration of this agent may suppress testosterone production by both the testes and the adrenals to castrate-range levels. Androgen sensitive prostatic carcinoma responds to treatment that decreases androgen levels. Androgen deprivation therapies, such as treatment with GnRH agonists or orchiectomy, decrease androgen production in the testes but do not affect androgen production by the adrenals or in the tumor.

Ketoconazole is an azole antifungal. Ketoconazole was the first broad-spectrum oral antifungal agent available to treat systemic and superficial mycoses. Evidence of hepatotoxicity associated with its use emerged within the first few years of its approval. Due to its hepatotoxic side effects, oral ketoconazole was withdrawn from the European and Australian markets in 2013. The United States imposed strict relabeling requirements and restrictions for prescription, with Canada issuing a risk communication echoing these concerns. Today, oral ketoconazole is only indicated for endemic mycoses, where alternatives are not available or feasible. Meanwhile, topical ketoconazole is effective, safe, and widely prescribed for superficial mycoses, particularly as the first-line treatment for tinea versicolor. Topically administered ketoconazole is usually prescribed for fungal infections of the skin and mucous membranes, such as athlete's foot, ringworm, candidiasis (yeast infection or thrush), jock itch, and tinea versicolor. Topical ketoconazole is also used as a treatment for dandruff (seborrheic dermatitis of the scalp) and for seborrheic dermatitis on other areas of the body, perhaps acting in these conditions by suppressing levels of the fungus Malassezia furfur on the skin. Ketoconazole interacts with 14-α demethylase, a cytochrome P-450 enzyme necessary for the conversion of lanosterol to ergosterol. This results in inhibition of ergosterol synthesis and increased fungal cellular permeability. Other mechanisms may involve the inhibition of endogenous respiration, interaction with membrane phospholipids, inhibition of yeast transformation to mycelial forms, inhibition of purine uptake, and impairment of triglyceride and/or phospholipid biosynthesis. Ketoconazole can also inhibit the synthesis of thromboxane and sterols such as aldosterone, cortisol, and testosterone. Ketoconazole is active against clinical infections with Blastomyces dermatitidis, Coccidioides immitis, Histoplasma capsulatum, Paracoccidioides brasiliensis.

Seviteronel (VT-464) is a 17,20-lyase selective inhibitor of CYP17A1, which plays key roles in adrenal and intratumoral de novo biosynthesis of androgens. The inhibition of 17,20-lyase activity by seviteronel (VT-464) is enough to reduce androgen levels, and its preserving of 17alpha-hydroxylase activity largely avoids interference with the production of other steroidal hormones. Seviteronel (VT-464) also has shown AR-antagonist activity independent of CYP17 enzyme inhibition. It is currently in phase 2 clinical trials as a therapeutic for castration-resistant prostate cancer patients.

Galeterone (TOK-001, formerly called VN/124-1) is a potent anti-androgen with three modes of action. The compound acts as a specific androgen receptor antagonist, inhibits CYP17 lyase while conserving CYP17 hydroxylase function, and decreases overall androgen receptor levels in prostate cancer cells. Galeterone is a first in class, multi-targeted small-molecule drug that disrupts the growth and survival of prostate cancer cells. Tokai Pharmaceuticals is developing galeterone as an oral treatment for castration-resistant prostate cancer. Phase III clinical development of galeterone is underway in the US, Canada, Australia, Western Europe, Spain and the United Kingdom.

Orteronel (TAK-700) is a non-steroidal antiandrogen, discovered by Takeda Pharmaceutical Company Limited, that selectively inhibits the 17,20 lyase enzyme (CYP17A1). This enzyme, which is present in both the testes and adrenal glands, is central to the production of steroidal androgens. Synthesis of androgens outside the testes contributes to disease progression in castration-resistant prostate cancer (CRPC). In phase III of clinical trials for metastatic, hormone-refractory prostate cancer it wasn’t shown overall survival rates, and development was voluntarily terminated as a result.

Mono(ethylhexyl) phthalate (MEHP) is an active metabolite of Bis(2-ethylhexyl)phthalate (DEHP). DEHP is a widely used plasticizer. MEHP has been shown to be moderately toxic. Studies involving orally administered MEHP revealed the mild hepatic changes occurred but there was no bioaccumulation of the monoester. Studies of the rat and rabbit indicated that MEHP has no teratogenic effects. This compound was readily absorbed from the gastrointestinal tract. Radioactivity following intravenous administration of 14C-MEHP was rapidly distributed in tissues, with the highest levels occurring in the liver, kidney, and urinary bladder. Mono(ethylhexyl) phthalate is a member of a class of chemical compounds with known adverse effects on the male reproductive system.

Abiraterone acetate (trade name Zytiga) is a prodrug to the abiraterone, steroidal compound with antiandrogen activity and a 17 α-hydroxylase/C17,20-lyase (CYP17) inhibitor. It is indicated in combination with prednisone for the treatment of patients with metastatic castration-resistant prostate cancer. Abiraterone acetate is converted in vivo to abiraterone which inhibits CYP17, enzyme expressed in testicular, adrenal, and prostatic tumor tissues and required for androgen biosynthesis. Administration of this agent may suppress testosterone production by both the testes and the adrenals to castrate-range levels. Androgen sensitive prostatic carcinoma responds to treatment that decreases androgen levels. Androgen deprivation therapies, such as treatment with GnRH agonists or orchiectomy, decrease androgen production in the testes but do not affect androgen production by the adrenals or in the tumor.

Ketoconazole is an azole antifungal. Ketoconazole was the first broad-spectrum oral antifungal agent available to treat systemic and superficial mycoses. Evidence of hepatotoxicity associated with its use emerged within the first few years of its approval. Due to its hepatotoxic side effects, oral ketoconazole was withdrawn from the European and Australian markets in 2013. The United States imposed strict relabeling requirements and restrictions for prescription, with Canada issuing a risk communication echoing these concerns. Today, oral ketoconazole is only indicated for endemic mycoses, where alternatives are not available or feasible. Meanwhile, topical ketoconazole is effective, safe, and widely prescribed for superficial mycoses, particularly as the first-line treatment for tinea versicolor. Topically administered ketoconazole is usually prescribed for fungal infections of the skin and mucous membranes, such as athlete's foot, ringworm, candidiasis (yeast infection or thrush), jock itch, and tinea versicolor. Topical ketoconazole is also used as a treatment for dandruff (seborrheic dermatitis of the scalp) and for seborrheic dermatitis on other areas of the body, perhaps acting in these conditions by suppressing levels of the fungus Malassezia furfur on the skin. Ketoconazole interacts with 14-α demethylase, a cytochrome P-450 enzyme necessary for the conversion of lanosterol to ergosterol. This results in inhibition of ergosterol synthesis and increased fungal cellular permeability. Other mechanisms may involve the inhibition of endogenous respiration, interaction with membrane phospholipids, inhibition of yeast transformation to mycelial forms, inhibition of purine uptake, and impairment of triglyceride and/or phospholipid biosynthesis. Ketoconazole can also inhibit the synthesis of thromboxane and sterols such as aldosterone, cortisol, and testosterone. Ketoconazole is active against clinical infections with Blastomyces dermatitidis, Coccidioides immitis, Histoplasma capsulatum, Paracoccidioides brasiliensis.