ÎPharmacologic induction of drug tolerance to aspirin (eg, aspirin desensitization) is intended primarily for patients with aspirin- exacerbated respiratory disease (AERD), and unlike other types of desensitization its purpose is to cautiously induce (rather than prevent) a reaction, after which patients become tolerant of aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs). (B)
ÎSome induction of drug tolerance procedures have been described that appear to be successful through currently undefined mechanisms. (C)
ÎThe objective of a graded challenge is to cautiously introduce a drug in patients who are unlikely to be allergic to it. Unlike induction of drug tolerance, it does not modify patients' response to a drug. (D)
Specific Drugs
β-Lactam Antibiotics Penicillin
ÎApproximately 10% of patients report a history of penicillin allergy, but after complete evaluation, up to 90% of these individuals are able to tolerate penicillins. (B)
ÎTreatment of patients assumed to be penicillin allergic with alternate broad-spectrum antibiotics may compromise optimal medical care by leading to multiple drug-resistant organisms, higher costs, and increased toxic effects. (C)
ÎEvaluation of patients with penicillin allergy by skin testing leads to reduction in the use of broad-spectrum antibiotics and may decrease costs. (B)
ÎThe rate of penicillin-induced anaphylaxis after parenteral administration is approximately 1 to 2 per 10,000 treated patients. (C)
ÎPenicillin is immunologically inert and haptenates proteins after undergoing spontaneous conversion under physiologic conditions to reactive intermediates. These transformation products are known as penicillin major and minor antigenic determinants. (C)
ÎPenicillin skin testing is the most reliable method for evaluating IgE- mediated penicillin allergy. (B)
> Ideally, penicillin skin testing should be performed with both major and minor determinants. The negative predictive value of penicillin skin testing for immediate reactions approaches 100%, whereas the positive predictive value is between 40% and 100%. (B)
ÎSkin testing with the major determinant and penicillin G only (without penicilloate or penilloate) may miss up to 20% of allergic patients, but data on this are conflicting. (C)
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