Please cite this article in press as: Minciullo PL, et al. Challenge test to bisphosphonates in patients with hypersensitivity reactions to drugs. Allergol Immunopathol (Madr). 2014. http://dx.doi.org/10.1016/j.aller.2013.09.010 ARTICLE IN PRESS +Model ALLER-572; No. of Pages 4 Allergol Immunopathol (Madr). 2014;xxx(xx):xxx---xxx www.elsevier.es/ai ORIGINAL ARTICLE Challenge test to bisphosphonates in patients with hypersensitivity reactions to drugs Paola Lucia Minciullo a , Alessandro Allegra b,* , Anna D’Angelo a , Caterina Musolino b , Sebastiano Gangemi a,c a Department of Clinical and Experimental Medicine, School and Division of Allergy and Clinical Immunology, University of Messina, Messina, Italy b Division of Haematology, University of Messina, Messina, Italy c Institute of Biomedicine and Molecular Immunology ‘‘A. Monroy’’ (IBIM), Consiglio Nazionale delle Ricerche (CNR), Palermo, Italy Received 19 August 2013; accepted 23 September 2013 KEYWORDS Bisphosphonates; Challenge test; Drug reaction; Safety; Hypersensitivity reactions; Cutaneous reactions Abstract Background: Bisphosphonates are a commonly used class of drugs with known efficacy in the prevention and treatment of postmenopausal and steroid-induced osteoporosis, Paget’s dis- ease of bone, hypercaelcemia of malignancy, osteolytic lesions of multiple myeloma, and bone metastases. Nitrogen-containing bisphosphonates have a favourable tolerability and safety pro- file, cutaneous reactions have been reported. Methods: This is a retrospective case series study, based on the analysis of data from 1429 patients admitted to the Allergy and Clinical Immunology Division of the University of Messina between January 2011 and December 2012. Most patients had previous adverse drug reactions (ADRs) and referred to us for a challenge test with an alternative drug. Results: We observed six patients with a past history of adverse drug reaction who needed to be tested for bisphosphonates: three patients for risedronate, two for clodronate and one for alendronate. In two years only two patients were referred to us for an adverse reaction to bisphosphonates: one to alendronate and one to risedronate. Another patient presented a previous reaction to strontium ranelate. The other three patients reported previous hypersen- sitivity reactions to at least two different classes of drugs. All the patients experienced no reaction using the tested drugs. Conclusions: In our experience drug challenge tests for bisphosphonates are safe and reliable. © 2013 SEICAP. Published by Elsevier España, S.L. All rights reserved. * Corresponding author. E-mail addresses: alessandro.allegra@tin.it, aallegra@unime.it (A. Allegra). Introduction Bisphosphonates (BPs) are drugs made up of two phosphonic acids joined to a carbon plus two side chains. 1 0301-0546/$ – see front matter © 2013 SEICAP. Published by Elsevier España, S.L. All rights reserved. http://dx.doi.org/10.1016/j.aller.2013.09.010