The nocebo effect during oral challenge in subjects with adverse drug reactions.

BACKGROUND Nocebo effect is the occurrence of troublesome symptoms after the administration of inert substances. It can be easily studied during blind oral challenges for drug reactions, which always involve the administration ofa placebo. METHODS We collected data about nocebo effect in outpatients undergoing oral drug challenge. Patients with previous documented adverse reactions to drugs underwent an oral challenge with alternative drugs to identify the compounds that can be safely used The challenges involved the administration of aplacebo before the active drugs and were performed under medical supervision. RESULTS Four hundred and thirty-five patients (18-68 yrs, 68% female) underwent the oral drug challenge. Most of them (52%) had a previous reaction with antibiotics and non-steroidal antinflammatory drugs. The reported reactions were urticaria (and/or angioedema), respiratory complaints, generalized itching and non-specific symptoms. A nocebo effect was seen in 13patients (3%), (10 female). The majority of the observed effects were subjective (malaise, itching, abdominal pain). No special demographic or clinical characteristic could be identified in the nocebo reactors. Ten/13 patients had an abnormal result at the hospital anxiety depression questionnaire. CONCLUSION Nocebo effect was not negligible in this procedure, although lessfrequent than previously reported.