What is the purpose of ketoconazole in a patient with Cushing's disease?

Ketoconazole is used in the treatment of Cushing's disease primarily to decrease cortisol levels. Cushing's disease is characterized by excessive production of cortisol, often due to a tumor in the pituitary gland that secretes adrenocorticotropic hormone (ACTH), leading to adrenal hyperplasia and overproduction of cortisol. Ketoconazole is an antifungal medication that also possesses the ability to inhibit steroidogenesis, which means it can lower the synthesis of corticosteroids in the adrenal cortex.

By inhibiting enzymes involved in cortisol production, ketoconazole effectively reduces the elevated cortisol levels associated with this condition. This therapeutic effect helps alleviate the symptoms of Cushing's disease, such as weight gain, hypertension, and electrolyte imbalances, ultimately improving the patient's overall well-being.

In contrast, the other options do not align with ketoconazole's pharmacological action or purpose in treating Cushing's disease. The drug does not aim to increase cortisol levels, enhance immune function, or improve bone density; rather, its primary role is to suppress the overproduction of cortisol, thus addressing the hypercortisolism that defines the disease.