Tolerability of a selective cyclooxygenase-2 inhibitor (Rofecoxib) in patients with pseudoallergic reactions to nonsteroid anti-inflammatory drugs

Background and objective: Pseudoallergic reactions triggered by nonsteroida l anti-inflammatory drugs (NSAIDs) are common and caused by inhibition of t he enzyme cyclooxygenase-l, whereas their therapeutic effects are mediated by inhibition of cyclooxygenase-2. This study analyzed the tolerability of the selective cyclooxygenase-2-inhibitor rofecoxib in patients who encounte red pseudoallergic reactions to NSAIDs. Patients and methods: 37 patients (12 males, 25 females, mean age 35 years [15-75 years]) with a history of pseudoallergic reactions to NSAIDs underwe nt standardized skin prick, scratch and patch tests along with oral placebo -controlled blinded exposure to rofecoxib (maximum single dose 12,5mg, cumu lative dose 25 mg). Results: 23 patients had skin reactions, 4 times respiratory symptoms were ducumented, and in 10 cases cutaneous as well as respiratory symptoms were reported. Salicylic acid was identified as the most common trigger for a ps eudoallergic reaction (n = 28). In 9 cases several non-steroidal antiphlogi stics of different chemical groups caused symptoms. All skin tests showed n egative results. Oral challenge with rofecoxib was tolerated by all 37 pati ents without adverse effects. Conclusion: Given the high incidence of pseudoallergic reactions to NSAIDs the use of selective cyclooxygenase-2-inhibitors represents a therapeutic a lternative as well as a means of prevention of the described reactions.