Acetaminophen has greater antipyretic efficacy than aspirin in endotoxemia: a randomized, double-blind, placebo-controlled trial.

Objective: To compare the antipyretic efficacy of aspirin and acetaminophen (INN, paracetamol) in 30 male volunteers with the use of endotoxin (lipopolysaccharide) to elicit a standardized febrile response.

Methods: A randomized, double-blind, placebo-controlled trial was conducted in parallel groups. Subjects received an intravenous endotoxin bolus of 4 ng/kg after premedication with either placebo, 1000 mg aspirin, or 1000 mg acetaminophen by mouth.

Results: Peak body temperatures were 38.5 degrees C +/- 0.2 degrees C in the placebo group, 37.6 degrees C +/- 0.2 degrees C in the acetaminophen group (P = .001 versus placebo), and 38.6 degrees C +/- 0.2 degrees C in the subjects treated with aspirin (P = .001 versus acetaminophen; P = .570 versus placebo) at 4 hours after lipopolysaccharide infusion. Subjective symptom scores for chills and perception of fever were higher in the placebo group than in the acetaminophen group (chills, 2.5 +/- 0.3 versus 1.0 +/- 0.2, P = .009 and fever, 2.5 +/- 0.2 versus 2.0 +/- 0.2, P = .021). Tumor necrosis factor-alpha, interleukin-6, and interleukin-8 levels rose by several orders of magnitude (P < .001 versus baseline in all groups), without significant intergroup differences.

Conclusions: Acetaminophen was the superior antipyretic drug in endotoxemia compared with aspirin. Treatment with acetaminophen ameliorates subjective symptoms induced by endotoxemia without compromising the humoral response of a subject to endotoxin. This observation has clinical interest and may also help to improve the lipopolysaccharide model, which can be used to test anti-inflammatory and anticoagulatory drugs.