Once an individual has had an allergic reaction to a drug, he or she should avoid that medication. Also, an individual should always inform healthcare providers of any drug allergy. People who develop severe reactions or shock from a drug should carry medical alert cards or wear ID bracelets. These devices help inform providers of the allergy in emergency situations. The drugs used can all have side effects.
Antihistamines can cause sleepiness.
Prednisone can cause stomach problems, sleep problems, and mood swings. These side effects are generally very mild. Asthma medications can cause shakiness and abnormal heart rate. These, too, tend to be mild. Epinephrine can cause significant anxiety, shakiness, as well as abnormal heart rate.