Corticosteroids are a group of natural and synthetic analogs (chemical cousins) of the hormones secreted by the pituitary gland, also known as the hypothalamic-anterior pituitary-adrenocortical (HPA) axis. These analogs include glucocorticoids, which are anti-inflammatory agents with a large number of other functions; mineralocorticoids, which control salt and water balance primarily through action on the kidneys; and corticotropins, which control secretion of hormones by the pituitary gland.
Glucocorticoids have multiple effects, and are used for a large number of conditions. They affect glucose utilization and fat metabolism, bone development, and are potent anti-inflammatory agents. They may be used for replacement of natural hormones in patients with pituitary deficiency (Addison's disease), as well as for a wide number of other conditions including arthritis, asthma, anemia, various cancers, and skin inflammations. Additional uses include inhibition of nausea and vomiting after chemotherapy, treatment of septic shock, treatment of spinal cord injuries, and treatment of hirsutism (excessive hair growth). The choice of drug will vary with the condition.
Cortisone and hydrocortisone, which have both glucocorticoid and mineralocorticoid effects, are the drugs of choice for replacement therapy of natural hormone deficiency. Synthetic compounds, which have greater anti-inflammatory effects and less effect on salt and water balance, are usually preferred for other purposes. These compounds include dexamethasone, which is almost exclusively glucocorticoid in its actions, as well as prednisone, prednisolone, betamethasone, trimacinolone, and others. Glucocorticoids are formulated in oral dosage forms, topical creams and ointments, oral and nasal inhalations, rectal foams, and ear and eye drops.
Mineralocorticoids control the retention of sodium in the kidneys. In mineralocorticoid deficiency, there is excessive loss of sodium through the kidneys, with resulting water loss. Fludrocortisone (Florinef) is the only drug available for treatment of mineralocorticoid deficiency, and is available only in an oral form.
Corticotropin (ACTH, adrenocorticotropic hormone) stimulates the pituitary gland to release cortisone. A deficiency of corticotropic hormone will have the same effects as a deficiency of cortisone. The hormone, which is available under the brand names Acthar and Actrel, is used for diagnostic testing to determine the cause of a glucocorticoid deficiency. It is rarely used for replacement therapy, however, since direct administration of glucocorticoids may be easier and offers better control over dosages.
Dosage of glucocorticoids varies with drug, route of administration, condition being treated, and patient.
Fludrocortisone, for use in replacement therapy, is normally dosed at 0.1 mg/day. Some patients require higher doses. It should normally be taken in conjunction with cortisone or hydrocortisone.
ACTH, when used for diagnostic purposes, is given as 10 to 25 units by intravenous solution over eight hours. A long-acting form, which may be used for replacement therapy, is given by subcutaneous (SC) or intramuscular (IM) injection at a dose of 40 to 80 units every 24–72 hours.
The most significant risk associated with administration of glucocorticoids is suppression of natural corticosteroid secretion. When the hormones are administered, they suppress the secretion of ACTH, which in turn reduces the secretion of the natural hormones. The extent of suppression varies with dose, drug potency, duration of treatment, and individual patient response. While suppression is seen primarily with drugs administered systemically, it can also occur with topical drugs such as creams and ointments, or drugs administered by inhalation. Abrupt cessation of corticosteroids may result in acute adrenal crisis (Addisonian crisis) which is marked by dehydration with severe vomiting and diarrhea, hypotension, and loss of consciousness. Acute adrenal crisis is potentially fatal.
Chronic overdose of glucocorticoids leads to Cushingoid syndrome, which is clinically identical to Cushing's syndrome. The only difference is that in Cushingoid, the excessive steroids are from drug therapy rather than excessive glandular secretion. Symptoms vary, but most people have upper body obesity, rounded face, increased fat around the neck, and thinning arms and legs. In its later stages, this condition leads to weakening of bones and muscles with rib and spinal column fractures.
The short-term adverse effects of corticosteroids are generally mild, and include indigestion, increased appetite, insomnia, and nervousness. There are also a very large number of infrequent adverse reactions, the most significant of which is drug-induced paranoia. Delirium, depression, menstrual irregularity, and increased hair growth are also possible.
Long-term use of topical glucocorticoids can result in thinning of the skin. Oral steroid inhalations may cause fungal overgrowth in the oral cavity. Patients must be instructed to rinse their mouths carefully after each dose.
Corticosteroids are included in pregnancy category C. The pregnancy category system classifies drugs according to their established risks for use during pregnancy. Corticosteroids have caused congenital malformations in animal studies, including cleft palate. Breastfeeding while taking these medications should be avoided.
Because fludrocortisone has glucocorticoid activity as well as mineralocorticoid action, the same hazards and precautions apply to fludrocortisone as to the glucocorticoids. Overdose of fludrocortisone may also cause edema (swelling), hypertension, and congestive heart failure.
Corticotropin has all the same risks as the glucocorticoids. Prolonged use may cause reduced response to the stimulatory effects of corticotropin.
Patients with the following conditions should use corticosteroids with caution:
Corticosteroids interact with many other drugs a patient might take. Patients should inform their doctor about all other medications (both prescription and over-the-counter) they take, and discuss possible interactions.
Brody, T. M., J. Larner, K. P. Minneman, and H. C. Neu. Human Pharmacology: Molecular to Clinical, 2nd ed. St. Louis: Mosby Year-Book, 1998.
Griffith, H. W., and S. Moore. 2001 Complete Guide to Prescription and Nonprescription Drugs. New York: Berkely Publishing Group, 2001.
American Academy of Allergy, Asthma and Immunology. 611 East Wells Street, Milwaukee, WI 53202. Telephone: (414) 272–6071. Web site: http://www.aaaai.org .
Asthma and Allergy Foundation of America. 1125 15th Street NW, Suite 502, Washington, DC 20005. Telephone: (800) 727–8462. Web site: http://www.aafa.org .
National Heart, Lung and Blood Institute. National Institutes of Health, P.O. Box 30105, Bethesda, MD 20824-0105. Telephone: (301) 251–1222. http://www.nhlbi.nih.gov/nhlbi/nhlbi.htm .
Samuel Uretsky, PharmD