glucocorticoid therapy

Glucocorticoid therapy is the use of cortisol-like steroid drugs, and it wears two very different hats. The first is replacement: when the adrenal glands cannot make enough cortisol, a physiological dose simply restores what the body is missing, just as thyroid hormone is replaced in an underactive thyroid. The second is pharmacological: much larger doses are used to powerfully calm inflammation and dampen the immune system in conditions ranging from asthma to autoimmune disease.

Cortisol's natural job — preparing the body to handle stress, mobilizing glucose, and restraining inflammation — explains both uses. At replacement doses the goal is to copy the gland's normal daily output, including the morning-high pattern. At high anti-inflammatory doses the same actions are pushed far beyond physiology, which is therapeutically powerful but comes at the price of side effects.

Prolonged high-dose steroids can cause weight gain, high blood sugar, thinning bones, infections, and a drug-induced Cushing's syndrome. Crucially, they also suppress the body's own cortisol-producing axis, so stopping abruptly after long use can trigger a dangerous adrenal crisis; such therapy must be tapered slowly, and patients on replacement need to increase their dose during illness or surgery to mimic the body's natural stress response.