A nurse is caring for a client with Addison's disease. Which medication should the nurse administer to replace cortisol levels?

In the management of Addison's disease, the primary concern is the deficiency of adrenal hormones, particularly cortisol. The correct medication to replace cortisol levels is hydrocortisone. This medication is a synthetic form of cortisol and is utilized in hormone replacement therapy for patients with adrenal insufficiency. Administering hydrocortisone helps to regulate metabolism, immune response, and stress responses by providing the necessary glucocorticoid that the adrenal glands fail to produce adequately in Addison's disease.

Hydrocodone, although it is an opioid medication for pain relief, does not play any role in hormone replacement. Hydrochlorothiazide is a diuretic used to treat hypertension and fluid retention, which is unrelated to cortisol replacement. Hydrochloric acid serves as a digestive aid in the stomach and has no relevance in the context of hormone therapy. Therefore, hydrocortisone is the most appropriate choice for restoring cortisol levels in a client with Addison's disease.