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Central analgesic effect of acetaminophen but not of aspirin
Author(s) -
Piletta Pierre,
Porchet Hervé C,
Dayer Pierre
Publication year - 1991
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/clpt.1991.40
Subject(s) - acetaminophen , analgesic , aspirin , placebo , crossover study , anesthesia , medicine , nociception , clinical pharmacology , threshold of pain , pharmacology , receptor , alternative medicine , pathology
The central nervous system effect of acetaminophen (paracetamol) and acetylsalicylic acid was investigated in healthy volunteers according to a crossover, double‐blind, and placebo‐controlled design. Ten subjects received, by intravenous route, a placebo, 1 gm acetaminophen, and 1 gm acetylsalicylic acid. Analgesia was assessed by measurement of the subjective pain threshold and the objective nociceptive flexion reflex threshold in response to selective transcutaneous electrical stimulations. A close correlation was observed between subjective and objective pain thresholds. Acetaminophen increased both thresholds for more than 4 hours (24% and 23% of baseline value at 120 minutes, respectively; p < 0.001, ANOVA). In contrast, acetylsalicylic acid had no noticeable effect on either threshold. These findings show that acetaminophen‐induced analgesia is centrally mediated, in contrast to aspirin. The time delay between plasma concentration kinetics and acetaminophen analgesic effect is another argument in favor of its direct action on the central nervous system. Clinical Pharmacology and Therapeutics (1991) 49, 350–354; doi: 10.1038/clpt.1991.40