Cross-sensitization between sulfonamides and celecoxib has been discussed in the last years (1–4), although a real cross-reactivity between them has not been demonstrated.
We report here five patients with sulfamethoxazole allergy confirmed by single-blind placebo-controlled oral challenge (SBPCOC) who tolerated oral challenge tests with celecoxib. We recruited patients that had been diagnosed of sulfonamide allergy confirmed by a positive oral provocation test in the last 4 years. Five patients were included in the study after obtaining written informed consent. The mean age of the sulfonamide allergy group of patients was 32 ± 12.21 years (mean ± SD), with a predominance of females (4 : 1), and all of them had a history of sulfomethoxazole allergy confirmed by SBPCOC as shown in Table 1. We performed SBPCOC with celecoxib reaching a cumulative dose of 200 mg obtaining a negative result in all patients.
|Patient number||Age (years)||Sex||Clinical symptoms in sulfamethoxazole oral challenge|
Celecoxib is usually avoided in patients who have demonstrated allergic reactions to sulfonamides although there is a controversy about possible cross-reactions between sulfonamides and celecoxib. In fact few cases of clinically relevant possible cross-sensitization between these two drugs have been reported in literature.
Celecoxib is a sulfonamide-containing drug without an aromatic amine and without a substituted ring at the N1-position, so it is chemically distinct from the arylamine sulfonamide antimicrobials, and these differences are responsible of the lower potential for causing hypersensitivity reactions of celecoxib (2, 3). A meta-analysis of 14 double-blind studies showed that celecoxib, nonsulfonamide-containing nonsteroidal anti-inflammatory drugs and placebo have comparable potentials for cross-reactivity with sulfonamide-containing drugs (4).
In this study, no cross-sensitization between celecoxib and sulfomethoxazole was found. Although further investigations are necessary, scientific data at the moment show no evidence to avoid using celecoxib in patients with a known sulfonamide allergy, at least until possible cross-reaction could be confirmed by an oral challenge with the cyclo-oxygenase-2 inhibitor agent.