Pharmacokinetic‐pharmacodynamic relationships of methadone infusions in patients with cancer pain Journal Article


Authors: Inturrisi, C. E.; Portenoy, R. K.; Max, M. B.; Colburn, W. A.; Foley, K. M.
Article Title: Pharmacokinetic‐pharmacodynamic relationships of methadone infusions in patients with cancer pain
Abstract: To determine the relationship between changes in plasma methadone concentration and pharmacodynamic effects, plasma methadone profiles and pharmacodynamics (analgesia and sedation) were measured during and after the continuous infusion of methadone for 180 to 270 minutes in 15 patients with pain caused by cancer. An increase in plasma methadone concentration resulted in a rapid increase in pain relief or sedation. The estimates of values of 50% of maximum effect (Css50) for pain relief and sedation obtained with a pharmacokinetic‐pharmacodynamic model varied tenfold to twentyfold among patients; the mean Css50 value for pain relief (0.359 ± 0.158 [SD] μg/ml) was virtually the same as the mean Css50 value for sedation (0.336 ± 0.205 [SD] μg/ml). Similarly, the mean γ (slope function) for pain relief (4.4 ± 3.8 [SD]) and sedation (5.8 ± 5.4 [SD]) did not differ. Examination of hysteresis plots of data obtained during the infusion and for 4 to 5 hours after cessation of the infusion revealed a very rapid equilibration between plasma methadone values and the sites mediating pain relief. There was no indication of the development of tolerance to the pharmacodynamic effects of methadone during the study. This report describes a method for quantitating the pharmacokinetic‐pharmacodynamic relationships of the desirable and undesirable effects of opioid analgesics. Clinical Pharmacology and Therapeutics (1990) 47, 565–577; doi: © 1990 American Society for Clinical Pharmacology and Therapeutics
Keywords: adult; clinical article; aged; neoplasms; pain; sedation; cancer pain; dose-response relationship, drug; drug monitoring; methadone; analgesia; infusions, intravenous; clinical trials; intravenous drug administration; blood level; middle age; radioimmunoassay; human; male; female; priority journal; article; support, non-u.s. gov't; support, u.s. gov't, p.h.s.
Journal Title: Clinical Pharmacology & Therapeutics
Volume: 47
Issue: 5
ISSN: 0009-9236
Publisher: Nature Publishing Group  
Date Published: 1990-05-01
Start Page: 565
End Page: 577
Language: English
DOI: 10.1038/clpt.1990.77
PUBMED: 2188771
PROVIDER: scopus
DOI/URL:
Notes: Source: Scopus
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  1. Kathleen M Foley
    199 Foley
  2. Russell K. Portenoy
    165 Portenoy