Published Online: May 23, 2014
Drugs are responsible for 40% to 60% of anaphylactic reactions treated in the emergency room. Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most commonly used over-the-counter medications and although they can cause bronchospasm, urticaria, and angioedema in selected patients, they have not typically been recognized as a cause of anaphylaxis in emergency rooms.
In a study recently published in The Journal of Allergy and Clinical Immunology: In Practice, Aun and colleagues screened more than eight hundred patients seeking medical attention for adverse drug reactions at a university hospital in São Paulo, Brazil. The authors identified 117 patients with drug-induced anaphylaxis, assessing the culprit agents, the potential mechanism of the reactions, and the treatment provided. The authors also identified aggravating factors.
NSAIDs were the most frequently identified agents, causing 76% of all drug-induced anaphylactic reactions. NSAIDs reactions were defined as non-allergic, since an IgE-mediated mechanism was not demonstrated. More than 66% of the patients with anaphylaxis due to any medication had presented a prior adverse reaction to the drug involved in the anaphylactic reaction or to a drug from the same class/group. Epinephrine was used in only 34.2% of patients. IgE-mediated reactions were less common but more severe and were associated with cardiovascular dysfunction, hospitalization, and admission to the intensive care unit.
This large study revealed an unexpectedly high prevalence (>14%) of drug-induced anaphylaxis in patients seeking medical assistance for drug reactions. In contrast to other studies, Aun et al found that NSAIDs are the most common drugs involved in drug-induced anaphylaxis in Brazil. Anaphylaxis could potentially be avoided since patients were often re-exposed to drugs associated with previous reactions. Epinephrine was also underutilized for drug-induced anaphylaxis treatment in emergency services. The study shows the importance of an allergy evaluation for patients with adverse drug reactions, providing optimal diagnostic and preventative information.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.