A powerful corticosteroid drug sometimes prescribed for the treatment of severe asthma, rheumatoid arthritis, or other disorders. This drug is generally given in a short course of high doses (2/day for about three days), as prolonged use causes bad side effects, including diabetes, peptic ulcers, and high blood pressure.

Because asthma attacks are basically episodes of acute inflammation of the bronchi, a short course of prednisone can suppress the inflammation and speed recovery. Prednisone, like most corticosteroids, causes a limited form of dependence very slowly over a long period of time. Thus, short courses of fairly high doses are common for asthmatics (especially when sick with colds, bronchitis, etc). Dangers of withdrawal complications (due to suppression of natural hydrocortisone production) generally occur only with long-term treatment.

(Summarized from AMA literature)