Chapter 36: Adrenocortical Agents

Adrenocortical Agents agents, which include glucocorticoids and mineralocorticoids, are steroid hormones synthesized by the adrenal cortex; they are distinct from the adrenal medulla, which functions as a sympathetic ganglion releasing norepinephrine and epinephrine. The synthesis and secretion of these hormones are tightly regulated by the hypothalamic–pituitary axis (HPA), where the hypothalamus releases CRH (corticotropin-releasing hormone), triggering the pituitary to release ACTH (adrenocorticotropic hormone), which then stimulates the adrenal cortex. This process follows a diurnal rhythm, resulting in peak hormone levels between 6 and 9 AM in day-oriented people, which is why patients taking replacement doses like prednisone are instructed to take them upon awakening to minimize HPA axis suppression and mimic the natural cycle. Corticosteroids are crucial during the stress response, as they help the body conserve energy by increasing blood volume, releasing glucose, slowing protein production, and blocking inflammatory and immune activities. Glucocorticoids (e.g., prednisone, hydrocortisone) promote the preservation of energy by increasing blood glucose levels, stimulating fat deposition (lipogenesis), and increasing protein breakdown. Their potent clinical use stems from their antiinflammatory and immunosuppressive effects, achieved by blocking inflammatory mediators (prostaglandins and leukotrienes) and impairing the actions of phagocytes and lymphocytes. Mineralocorticoids, such as fludrocortisone, regulate electrolyte balance by increasing sodium and water retention and promoting potassium excretion, and are typically used in conjunction with glucocorticoids for adrenal insufficiency replacement therapy. Pathological conditions include adrenal excess, known as Cushing syndrome (characterized by central obesity, hypertension, protein breakdown, and a moon-like face), and adrenal insufficiency (e.g., Addison disease). Prolonged use of exogenous corticosteroids suppresses the HPA axis, leading to adrenal atrophy and requiring a slow dose tapering process to prevent a life-threatening adrenal crisis upon abrupt cessation. Adverse effects are often exaggerated physiological responses, including fluid retention, risk of peptic ulcer formation, immunosuppression, and potential growth retardation in children. Nursing interventions prioritize protecting the patient from infection, monitoring for signs of adrenal insufficiency or fluid overload, and ensuring thorough patient teaching, especially noting the increased toxicity risk of methylprednisolone in African Americans.