Ondansetron anaphylaxis: a case report and protocol for skin testing

Abstract

Editor—Ondansetron hydrochloride is a selective serotonin (5-HT3) receptor antagonist used as an antiemetic agent. Hypersensitivity reactions to ondansetron are rare but have been reported.1Ross AK Ferrero-Conover D Anaphylactoid reaction due to the administration of ondansetron in a pediatric neurosurgical patient.Anesth Analg. 1998; 87: 779-780PubMed Google Scholar, 2Weiss KS Anaphylactic reaction to ondansetron.Arch Intern Med. 2001; 161: 2263Crossref PubMed Scopus (9) Google Scholar, 3Chen M Tanner A Gallo-Torres H Anaphylactoid-anaphylactic reactions associated with ondansetron.Ann Intern Med. 1993; 119: 862Crossref PubMed Scopus (13) Google Scholar, 4Bousquet PJ Co-Minh HB Demoly P Isolated urticaria to ondansetron and successful treatment with granisetron.Allergy. 2005; 60: 543-544Crossref PubMed Scopus (14) Google Scholar Both IgE-mediated2Weiss KS Anaphylactic reaction to ondansetron.Arch Intern Med. 2001; 161: 2263Crossref PubMed Scopus (9) Google Scholar and non-IgE-mediated1Ross AK Ferrero-Conover D Anaphylactoid reaction due to the administration of ondansetron in a pediatric neurosurgical patient.Anesth Analg. 1998; 87: 779-780PubMed Google Scholar 5Kossey JL Kwok KK Anaphylactoid reactions associated with ondansetron.Ann Pharmacother. 1994; 28: 1029-1030Crossref PubMed Scopus (16) Google Scholar anaphylactic reactions to ondansetron have been rarely described as has isolated urticaria.4Bousquet PJ Co-Minh HB Demoly P Isolated urticaria to ondansetron and successful treatment with granisetron.Allergy. 2005; 60: 543-544Crossref PubMed Scopus (14) Google Scholar A 44-yr-old female was given ondansetron, vecuronium, and propofol at induction for elective surgery. She immediately became hypotensive with an arterial pressure of 60/30 mm Hg. There was no accompanying urticaria, angioedema, or respiratory distress. She was given i.v. epinephrine, promethazine, hydrocortisone, and fluids, after which she became normotensive. Mast cell degranulation was shown by an elevated serum tryptase level (48 μg litre−1, normal 0–13.5 μg litre−1) measured 4 h after the onset of hypotension. Her tryptase level was normal when measured 8 h after the onset of hypotension. The patient was investigated subsequently with skin prick and intradermal testing to her induction medications. Ten normal controls were used to determine the irritant concentration of ondansetron. The patient had an absent response upon skin prick testing at a concentration of 2 mg ml−1, but did demonstrate a positive wheal reaction on intradermal testing to ondansetron at a concentration of 0.02 mg ml−1. None of the 10 controls produced a positive intradermal test reaction at this concentration. Five of the controls developed a positive reaction with intradermal testing at a concentration of 0.2 mg ml−1 and nine of the controls at a concentration of 2 mg ml−1. The patient did not demonstrate a positive reaction to vecuronium, propofol, or latex. We suggest that a concentration of 0.02 mg ml−1 be used for intradermal testing in the evaluation of suspected ondansetron allergy. This is in contrast to the only previous case report of a confirmed ondansetron IgE-mediated hypersensitivity, where a concentration of 0.2 mg ml−1 was used to elicit a positive reaction.4Bousquet PJ Co-Minh HB Demoly P Isolated urticaria to ondansetron and successful treatment with granisetron.Allergy. 2005; 60: 543-544Crossref PubMed Scopus (14) Google Scholar This concentration was found to be irritant in our control group.