corticosteroid
Meaning of corticosteroid: Two jobs sit under one name, calming inflammation and holding on to salt, and each drug leans toward one or the other.
Definition of corticosteroid
A corticosteroid is any of the steroid hormones made by the adrenal cortex, the outer layer of the adrenal gland, or a manufactured drug copying one of them. They fall into two groups: glucocorticoids, which damp down inflammation and immune activity, and mineralocorticoids, which control the balance of sodium, potassium and body fluid.
What do the two groups do?
The adrenal cortex makes both, in response to different signals, and produces a third group of weak sex hormones alongside them.
| Group | Main natural hormone | What it controls |
|---|---|---|
| Glucocorticoid | Cortisol | Inflammation, immune activity, blood sugar, the response to stress |
| Mineralocorticoid | Aldosterone | Sodium and potassium handling by the kidney, and with it blood volume |
Cortisol output follows a daily rhythm set by a signal from the pituitary gland, and it rises further during illness or injury. Manufactured versions lean one way or the other rather than covering both evenly. Hydrocortisone, which is cortisol itself, has a foot in each camp and is used where the aim is to replace what a failing gland no longer makes. Dexamethasone is a strong glucocorticoid with almost no salt holding effect. Fludrocortisone is chosen for the opposite reason. The class is therefore not interchangeable, and selecting one is a decision about which of the two activities is wanted and how long it should last.
Why are they prescribed for so many different conditions?
Because inflammation runs through illnesses that otherwise have nothing in common. The same drug family is used in asthma, severe allergic reactions, inflammatory bowel disease, rheumatoid arthritis, many skin conditions and rejection after a transplant. Glucocorticoids also kill lymphocytes outright, which is why they form part of treatment for some lymphomas and lymphoid leukemias. A separate use is replacement, supplying the hormone when the adrenal glands cannot. The route is chosen to limit how far the drug travels: inhaled into the airway, rubbed into the skin, dropped into the eye or injected into a single joint, so that most of the effect stays where it is wanted.
How do they differ from other drugs called steroids?
Two confusions are worth separating. Anabolic steroids are copies of testosterone used to build muscle; they share the ring shaped chemical frame that makes any of these molecules a steroid, and little else. A nonsteroidal anti-inflammatory drug such as ibuprofen also reduces inflammation, but through a much narrower chemical pathway, which is precisely what the word nonsteroidal marks. Prolonged corticosteroid treatment carries well described consequences of its own, including thinning skin, easy bruising, raised blood sugar, loss of bone density and greater susceptibility to infection. It also quiets the body's own cortisol production, so a long course is normally reduced in steps rather than stopped outright.
Used in a sentence
A corticosteroid was prescribed to reduce the inflammation associated with the flare.
Good to know
Corticosteroid medications differ in how strongly they exhibit glucocorticoid versus mineralocorticoid activity, which is why one corticosteroid is often preferred over another for a particular purpose.
Word origin
Where “corticosteroid” comes from
Formed from Latin cortex, meaning bark or outer layer, referring to the adrenal cortex where these hormones originate.