Safety of the new selective cyclooxygenase type 2 inhibitors rofecoxib and celecoxib in patients with anaphylactoid reactions to nonsteroidal anti-inflammatory drugs. 
Controlled oral challenge with nonsteroidal anti-inflammatory drugs (NSAIDs) is the only definite way to detect safe NSAIDs in patients with NSAID-induced anaphylactoid reactions.  To evaluate the safety of the selective cyclooxygenase (COX) type 2 inhibitors rofecoxib and celecoxib in patients with single-reactive, NSAID-induced anaphylactoid reactions.  We prospectively conducted single-blind, placebo-controlled oral challenges (SBPCOCs) with rofecoxib and celecoxib in 33 patients with single-reactive, NSAID-induced anaphylactoid reactions.  Nineteen women and 14 men (age range, 20-78 years; mean age, 44.8 years) exhibited anaphylactoid reactions on emergency department admission.  Symptoms involved the skin (100%), laryngeal edema (73%), systolic hypotension (39%), and the gastrointestinal system (15%).  The NSAIDs most frequently involved in the episodes were dipyrone (64%), propyphenazone (12%), and diclofenac (12%).  In all patients, tolerance to a potent, nondiscriminatory COX inhibitor (except those reported as being responsible for the reaction) was noted.  The SBPCOCs with the selective COX-2 inhibitors celecoxib and rofecoxib were well tolerated in all cases.  Twenty-three patients who had an anaphylactoid reaction involving dipyrone and propyphenazone showed good tolerance to celecoxib (which contains a pyrazole group in its structure) on challenge.  The SBPCOCs with highly selective COX-2 inhibitors were safe in patients with single-reactive, NSAID-induced anaphylactoid reactions, even in cases that involved pyrazole derivatives.