MORPHINE (pharmacokinetic profile)

  1. Phenantherene opioid (morphine, hydromorphone and oxymorphone)
  1. As above.
  1. Can be given PO, IV, SC, Intra-thecal, PR
  1. Rapidly leaves blood compartment and accumulates in highly perfused tissues – brain, heart, lung, kidney and spleen.
  1. Hepatic – glucuronidation to morphine-3-glucuronide. 10% converted to morphine-6-glucuronide.
    • Readily excreted in kidneys.
    • Noted that M3G and M6G are very polar and tend not to contribute significantly to CNS effects if used acutely. However, they do accumulate in renal failure, if large doses are given or if used over prolonged period.
    • M3G may cause seizures.
    • M6G may cause prolonged opioid action.
  1. Urinary
Special notes
  1. Note that most opioids tend to have the same pharmacodynamic profile.