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Rescue factor: A design for evaluating long‐acting analgesics
Author(s) -
Savarese John J,
Thomas Gordon B,
Homesley Howard,
Stratton Hill C
Publication year - 1988
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.1988.46
Subject(s) - morphine , analgesic , crossover study , medicine , dosing , morphine sulfate , anesthesia , potency , pharmacology , chemistry , biochemistry , alternative medicine , pathology , in vitro , placebo
A design is described that uses need for supplemental (rescue) analgesic as a factor predicting effectiveness of a test analgesic. This methodology is especially suited for evaluating long‐acting analgesics given repeatedly. Rescue use is measured over dosing intervals as test drug is titrated from a subanalgesic dose to that requiring no or minimal rescue. This design was used to evaluate oral long‐acting morphine sulfate (MS Contin) given every 12 hours in a crossover study of cancer pain using oral immediate–release morphine sulfate given every 4 hours as reference. Less morphine was required for MS Contin given every 12 hours relative to immediate–release morphine sulfate given every 4 hours (186 ± 22 mg vs. 239 ± 35 mg; p = 0.04). Total daily morphine for both regimens correlated linearly (r = 0.96) with a slope of 1.27 ± 0.11, significantly (p = 0.03) different from equivalence (slope of unity) in favor of MS Contin. This design features assay sensitivity (dose‐response) and provides relative potency estimates for analgesics given at specific regimens. Clinical Pharmacology and Therapeutics (1988) 43, 376–380; doi: 10.1038/clpt.1988.46