Ondansetron anaphylaxis: a case report and protocol for skin testing
Sydney, Australia
* E-mail: sfernando{at}nsccahs.health.nsw.gov.au
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.1–4 Both IgE-mediated2 and non-IgE-mediated1 5 anaphylactic reactions to ondansetron have been rarely described as has isolated urticaria.4
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.4 This concentration was found to be irritant in our control group.
References
1 Ross AK, Ferrero-Conover D. Anaphylactoid reaction due to the administration of ondansetron in a pediatric neurosurgical patient. Anesth Analg (1998) 87:779–80.
2 Weiss KS. Anaphylactic reaction to ondansetron. Arch Intern Med (2001) 161:2263.
3 Chen M, Tanner A, Gallo-Torres H. Anaphylactoid-anaphylactic reactions associated with ondansetron. Ann Intern Med (1993) 119:862.
4 Bousquet PJ, Co-Minh HB, Demoly P. Isolated urticaria to ondansetron and successful treatment with granisetron. Allergy (2005) 60:543–4.[CrossRef][Web of Science][Medline]
5 Kossey JL, Kwok KK. Anaphylactoid reactions associated with ondansetron. Ann Pharmacother (1994) 28:1029–30.[Abstract]
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