Adverse drug reactions. A brief refresher on an ever-present hazard.

Adverse drug reactions are a major medical problem. There is a tendency on the part of the patient, and often the physician, to attribute almost any untoward reaction to an "allergy," while in reality there are numerous other possible causes. Despite the broad spectrum of clinical presentations and mechanisms of action, drug reactions are treated essentially by avoidance or discontinuation of the offending drug or drugs.