Aspirin and paracetamol tolerance in patients with nimesulide-induced urticaria

Background: The administration of aspirin and other nonsteroidal anti-inflammatory drugs in patients sensitive to nimesulide might be hazardous. Objective: To assess the tolerance to both acetaminophen (paracetamol) and aspirin in patients with a history of urticaria induced by nimesulide. Methods: Nine patients with a history of nimesulide intolerance were submitted to single-blind, placebo-controlled peroral challenges with increasing doses of acetaminophen and aspirin. Results: Acetaminophen was tolerated by all patients, whereas two experienced immediate systemic urticaria after the administration of 125 mg of aspirin. Conclusion: Acetaminophen and aspirin are well tolerated by most nimesulide-sensitive patients. Since a minority of patients show aspirin sensitivity, tolerance of this agent should always be ascertained by properly performed peroral challenges.