Treatment of allergic adverse drug reactions.

Allergic adverse drug reactions are unpredictable and dose-independent. The cellular events which comprise an allergic reaction cannot be effectively altered until we understand how, for instance, the provoking drug forms an immunoglobulin-like factor which releases chemical mediators of inflammation from effector cells, or how these mediators act on target tissues. Nor do we know how and why different patterns of drug allergy vary over time. The post hoc treatment of reactions is largely empirical and supportive, and depends on the type of reaction and its clinical setting. The treatment of acute severe reactions like analphylaxis include resuscitating the patient, ensuring airway patency, injecting adrenaline i.m., setting up an i.v. infusion of a plasma expander, and injecting an anti-histamine and hydrocortisone. After anaphylaxis the vital signs, the ECG, and respiratory function should be monitored in the intensive care unit; supportive drugs may be needed for 72 hours. Some other systemic disorders induced by allergic drug reactions are well defined, but their treatment is either nonspecific or highly specialised. Because disease and death due to drug allergy are becoming more frequent, clinicians must try to limit them by recording careful drug histories, using radiocontrast agents only when necessary, and prescribing drugs only when benefit will probably exceed risk. Doctors should also advise their patients against the misuse of drugs.