Drugs similar to the natural corticosteroid hormones produced by the adrenal gland
Corticosteroids are related to corticosteroid hormones produced by the body. The production of corticosteroid hormones by the adrenal glands is regulated by corticotropin, a pituitary hormone.
The main use for corticosteroid drugs is in the treatment of inflammatory conditions that may affect the joints, skin, digestive tract, respiratory system, eyes, and ears. These drugs are also prescribed as replacement therapy if the body is unable to produce sufficient natural corticosteroid hormones on its own (see Addison’s disease, and Hypopituitarism).
In addition, corticosteroids may be given as long-term treatment following transplant surgery because their action suppresses the body’s immune system. This action helps to prevent rejection of the transplanted organs or tissue.
How do they work?
Corticosteroids affect many body processes, including virtually all aspects of the inflammatory process. Their exact mechanism of action is unknown, but one of their effects is to reduce the production of prostaglandins, substances that play a key role in triggering inflammation. Corticosteroids also suppress the immune system by reducing the production and effectiveness of certain white blood cells that are an important part of the body’s immune response.
How are they used?
Corticosteroids can be given in a variety of ways. The drugs may be injected directly into body tissues near inflamed areas such as tendons and joints (see Locally acting corticosteroids). Used in this way, they may improve symptoms in joint disorders such as osteoarthritis and rheumatoid arthritis. Frequent injections are avoided because of the risk of side effects.
Topical corticosteroids in the form of creams and ointments are used to reduce inflammation and itching in some skin conditions. Corticosteroids may be used topically as suppositories, orally, or by injection to treat the gastrointestinal disorders ulcerative colitis and Crohn’s disease. Oral corticosteroids are used for severe rheumatoid arthritis and respiratory disorders such as asthma, sarcoidosis, and fibrosing alveolitis. They are also used after transplant surgery (see Immunosuppressants) and to treat Addison’s disease and hypopituitarism. Corticosteroids may be injected to treat severe Addison’s disease or anaphylaxis and can be given by inhaler to prevent asthma attacks (see Corticosteroids for respiratory disease).
What are the side effects?
Short-term use of corticosteroids rarely produces side effects. Such effects are also rare in long-term replacement therapy for Addison’s disease and hypopituitarism because the drugs replace the body’s natural hormones. Doctors use these drugs sparingly for other conditions because of side effects.
Prolonged use of strong topical corticosteroid drugs can damage the skin in the affected areas, causing thinning, wrinkling, and loss of pigmentation. Particular care is needed when using these drugs on the face or on a baby’s skin. Locally injected or inhaled corticosteroids are unlikely to cause serious side effects, but may cause local problems such as minor throat infections. Inhaled corticosteroids may also cause oral thrush.
Long-term treatment with oral corticosteroids may cause easy bruising, acne, a moon-shaped face, and weight gain (see Cushing’s syndrome). Prolonged use can also cause raised blood pressure and osteoporosis. Children taking these drugs will have their height monitored during treatment, as the drugs can slow growth. The risk of infections, especially viral infections, is increased by the drugs because they suppress the immune system.
Corticosteroids suppress the body’s own production of corticosteroid hormones. As a result, the body may not be able to produce sufficient corticosteroid hormones if treatment is stopped suddenly. An abrupt withdrawal from long-term, high-dose corticosteroids can lead to a rapid fall in blood pressure and, sometimes, shock, which can be fatal. If your doctor prescribes corticosteroid drugs for you for more than 3 weeks, you will be given a medical alert card that gives details of your medication to inform any health professional who treats you. You should avoid coming into contact with anyone with chickenpox or shingles because of the risk of a severe infection. If you develop an infection or if you sustain injuries, a higher dose of corticosteroids may be needed. If you are prescribed systemic corticosteroids (that is, when the drugs reach all parts of the body, rather than just a localized area), your doctor will give you a leaflet detailing precautions, side effects, and warnings about the drugs.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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