Acetaminophen and aspirin challenges in subgroups of asthmatics.

To determine whether the different modes of action of aspirin and acetaminophen are associated with different incidences of bronchoconstriction, and whether there is cross-reactivity in terms of intolerance, selected asthmatics were challenged with both analgesics. Clinical profiles were observed to characterize more precisely the aspirin-intolerant asthmatic. Inhalational challenges with PGF2 alpha were then performed on nine selected subjects. It was determined that a positive history of aspirin intolerance is a reliable indicator of potential for anaphylactoid reactions but is not associated with any detectable risk of acetaminophen intolerance. Inhalational PGF2 alpha tends to involve the larger airways; oral aspirin affects both large and small airways.