RATIONALE: Drug challenges may be used as a diagnostic tool in patients with questionable drug allergies. We determined the safety and outcomes of drug challenges.METHODS: We performed a 3-year retrospective chart review of adults who underwent drug challenges by our Allergy/Immunology Division after consultation deemed drug challenge to be appropriate. Most were 2-3 step graded challenges starting at 1/10th or 1/100th of the final dose. Challenged drugs included: antibiotics (62.5%), NSAIDs (11.4%), hormones, and other medications. All patients had reported reactions to the challenged drug.RESULTS: 96 patients (76% female) underwent 96 drug challenges; 82% as outpatients. Most common historical drug reactions in order of frequency included: urticaria/angioedema, unknown, and other cutaneous manifestations. All 96 patients successfully completed their drug challenge; no patients reacted to the full dose. Twenty patients (20.8%) had symptoms during early steps of the challenge. Of these 20 patients, 13 had symptoms with a subtherapeutic dose of drug, and 7 had symptoms with placebo. Symptoms included: isolated tongue, lip, and or throat tightening, lightheadedness (normotensive), nasal congestion, local flushing, erythema, pruritus, and tremor. However, only 2/20 patients had an objective reaction of flushing, erythema; one after placebo. No reactions required treatment. Ten patients received a SBPC; 7/10 reacted to placebo.CONCLUSIONS: Symptoms associated with drug challenges are relatively common; however, most are subjective, transient, and appear not to be related to the drug as they did not occur at full therapeutic doses. In select patients, drug challenges are extremely safe and useful in drug allergy management. RATIONALE: Drug challenges may be used as a diagnostic tool in patients with questionable drug allergies. We determined the safety and outcomes of drug challenges. METHODS: We performed a 3-year retrospective chart review of adults who underwent drug challenges by our Allergy/Immunology Division after consultation deemed drug challenge to be appropriate. Most were 2-3 step graded challenges starting at 1/10th or 1/100th of the final dose. Challenged drugs included: antibiotics (62.5%), NSAIDs (11.4%), hormones, and other medications. All patients had reported reactions to the challenged drug. RESULTS: 96 patients (76% female) underwent 96 drug challenges; 82% as outpatients. Most common historical drug reactions in order of frequency included: urticaria/angioedema, unknown, and other cutaneous manifestations. All 96 patients successfully completed their drug challenge; no patients reacted to the full dose. Twenty patients (20.8%) had symptoms during early steps of the challenge. Of these 20 patients, 13 had symptoms with a subtherapeutic dose of drug, and 7 had symptoms with placebo. Symptoms included: isolated tongue, lip, and or throat tightening, lightheadedness (normotensive), nasal congestion, local flushing, erythema, pruritus, and tremor. However, only 2/20 patients had an objective reaction of flushing, erythema; one after placebo. No reactions required treatment. Ten patients received a SBPC; 7/10 reacted to placebo. CONCLUSIONS: Symptoms associated with drug challenges are relatively common; however, most are subjective, transient, and appear not to be related to the drug as they did not occur at full therapeutic doses. In select patients, drug challenges are extremely safe and useful in drug allergy management.