New concepts in the management of adverse drug reactions.

Our understanding of drug reactions and their management has changed markedly in recent years with the development of several new concepts. Epidermal cell death seen in Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) may result from Fas-Fas ligand-mediated apoptosis. Intravenous immunoglobulin (IVIG) contains anti-Fas antibodies that can abrogate apoptosis. Most studies on IVIG in SJS and TEN reported improvement in arresting disease progression and reduction in time to healing. Furthermore, several studies have dispelled the myth of sulfonamide cross-reactivity. Immune-mediated reactions against antibacterial sulfonamides are directed against two unique side chains that non-antibacterial sulfonamides do not contain. Certain patients seem to have a genetic predisposition for "multiple drug sensitivities." Hence, they may react to several drugs that are not necessarily cross-reacting. Also, multiple studies have shown that IgE-mediated nonsteroidal anti-inflammatory drugs (NSAIDs) cross-reactivity is uncommon. Rather, it is cyclooxygenase (COX) 1 inhibition that results in pseudoallergic reactions to multiple NSAIDs. Several studies have indicated that selective COX-2 inhibitors can be safely administered in patients with aspirin-exacerbated respiratory disease and NSAID-induced cutaneous reactions, although their use has been curtailed by their cardiovascular side effects. Biological agents, such as infliximab, are being increasingly used for a variety of diseases and have caused adverse reactions in some patients. Studies differ as to whether concomitant immunosuppressive use with infliximab affects the development of drug-specific antibodies and infusion reactions. Successful desensitization protocols have been developed for reactions to some of these agents.