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A new method for rate of analgesic onset: Two doses of intravenous morphine compared with placebo
Author(s) -
Whitehead Elizabeth M,
O'Sullivan Geraldine M,
Lloyd Julia,
Bullingham Roy E S
Publication year - 1992
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.1992.130
Subject(s) - analgesic , placebo , morphine , medicine , anesthesia , clinical pharmacology , pharmacology , alternative medicine , pathology
A new method of frequent early pain assessments for 1 hour only was used to determine time of onset of analgesia after intravenous administration of 10 mg morphine, 5 mg morphine, or placebo in a double‐blind study; 79 patients were randomized if they required parenteral analgesia in the early postoperative period. Pain intensity was determined by a four‐point categoric verbal rating scale and on a verbal ordinal scale from 0 to 100 (0 = no pain, 100 = worst pain imaginable) during the first hour after analgesic administration. The onset time of analgesia, assessed by 50% of patients achieving 25% reduction from their baseline pain assessment, was significantly faster for 10 mg morphine compared with 5 mg morphine ( p = 0.02) and placebo ( p < 0.01). More familiar analgesic efficacy measures, including the sum of pain intensity differences and time to next analgesic dose, similarly showed the superiority of 10 mg morphine to placebo in the first hour, confirming sensitivity according to the conventional paradigm. Clinical Pharmacology and Therapeutics (1992) 52, 197–204; doi: 10.1038/clpt.1992.130