First, let me provide some background information. Prednisone is a type of medication called a glucocorticoid, or a corticosteroid. Glucocorticoids are used to treat conditions that involve inflammation, and they are generally very effective. Unfortunately, when they are taken over time by mouth, intravenously, or by injection, glucocorticoids have significant side effects. In contrast, if glucocorticoids are inhaled, such as in the treatment of asthma, the doses are much lower and there are minimal side effects, even with years of use. Finally, you should know that glucocorticoids are different from the anabolic steroids abused by athletes to enhance performance and increase muscle mass.

These are the most common side effects of Prednisone, grouped by the body system involved:

• General side effects: increased appetite, fluid retention, weight gain, increased blood sugar (which can lead to diabetes), change in body shape (increase in fatty tissue on the trunk while the arms and legs get thinner), increased susceptibility to infections, acne, thinning of the skin, easy bruising
• Heart and blood vessels: increase in blood pressure, unfavorable changes in cholesterol levels
• Stomach and intestines: irritation of lining of stomach and small intestine, ulcers, bleeding
• Eyes: early cataracts and glaucoma
• Muscles and bones: thinning of the bones leading to osteoporosis, muscle inflammation (rare)
• Brain and nervous system: mood changes (some people get "revved up" and have trouble sleeping, others get depressed), psychotic behavior (fortunately, this last problem is rare at doses below 20 mg daily)
• Response to stress: Taking glucocorticoids over a period of years can cause a problem called "adrenal suppression." This is when the body's own natural steroid production (made by the adrenal glands) is turned down or off, because the steroid supply is coming from an outside source. The problem is the body normally increases steroid production dramatically during times of stress (e.g. illness or prolonged physical stress) so if the adrenal glands are turned down over time, they may not be able to respond and make more natural steroid when needed. The affected person can develop low blood pressure, weakness, problems with their blood chemistries, and even become critically ill. The treatment is to temporarily give more corticosteroids until the stress has resolved. Because of this problem, it is important to inform doctors (or emergency room practitioners) whenever someone has been taking steroids for an extended period of time.

Now, let me offer some perspective on this long and frightening list. Not all people develop these side effects, and those who do are typically affected by only one or two of them. There is no particular dose at which these side effects are sure to develop, although doctors start to look for them if someone has needed ten mg of prednisone daily for a year or more.