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Epidural and intrathecal opiates: Cerebrospinal fluid and plasma profiles in patients with chronic cancer pain
Author(s) -
Max Mitchell B,
Inturrisi Charles E,
Kaiko Robert F,
Grabinski Patricia Y,
Li Choh Hao,
Foley Kathleen M
Publication year - 1985
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.1985.237
Subject(s) - morphine , medicine , cerebrospinal fluid , methadone , anesthesia , cancer pain , lumbar , intrathecal , drug , pharmacology , cancer , surgery
We studied the cerebrospinal fluid (CSF) and plasma concentration‐time profiles of morphine, methadone, and β‐endorphin after lumbar epidural or intrathecal injection in 17 patients with cancer. After epidural injection, all three drugs reached peak levels in lumbar CSF within 34 minutes that were 50 to 1300 times higher than free drug concentrations in plasma. The rate of decline of CSF levels correlated with drug lipid solubility (methadone [t ½ = 73 minutes] > morphine [126 minutes] > β‐endorphin [317 minutes]). Plasma levels were comparable with those after intragluteal injection of the same dose. In four patients given intrathecal morphine or methadone, CSF at the C 1–2 level contained high levels of morphine as early as 1 hour after injection, but levels of methadone were lower or undetectable. Three of 17 patients reported improved analgesia initially, but none were improved at 2 weeks after chronic therapy. We conclude that analgesia induced by intrathecal or epidural morphine injections is caused by drug acting at both spinal and supraspinal sites. The use of spinal opiates such as morphine is of limited value in patients whose pain is not adequately managed by high systemic doses of morphine‐like drugs. Clinical Pharmacology and Therapeutics (1985) 38 , 631–641; doi: 10.1038/clpt.1985.237