Background: Anaphylaxis to nonsteroidal anti-inflammatory drugs is tho
ught to depend on cycloxygenase inhibition coupled to upregulation of
5-lipoxygenase-dependent pathways. The introduction of leukotriene-rec
eptor antagonists afforded the opportunity to test this hypothesis. Th
ese agents provide at least partial protection against aspirin-induced
anaphylaxis during controlled challenges but we did not know whether
the level of protection was high enough to block symptoms from ingesti
on of a full dose of aspirin. Methods: We report a patient with modera
tely severe asthma who experienced an episode of anaphylaxis following
ingestion of 400 mg of ibuprofen while under therapy with 20 mg of za
firlukast given twice a day. Results: No further episodes of anaphylax
is have been noted following institution of complete avoidance to all
nonsteroidal anti-inflammatory drugs. Conclusions: Patients who are se
nsitive to cycloxygenase inhibitors should practice complete avoidance
of these drugs even while under therapy with leukotriene modifiers.