There is no way to prevent the development of an allergic reaction to a medication. Once a reaction has occurred, an individual should avoid that particular medicine. Rarely, a person will need to take a medication even if he or she is allergic to it. In those cases, the person can be pretreated with medicines that prevent the allergic response. These medicines include steroids, antihistamines, and epinephrine.
There are few long-term problems associated with an allergic reaction. In a few cases, the reaction will include severe asthma or shock. However, most people recover quickly.
Allergic reactions are not contagious. They pose no risk to others.