Preparation for Child Psych PRITE and Boards
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Introduction

Opioids are widely used, but often misused and underutilized in clinical practice. They are also widely abused.

Strong Agonists

  • morphine (pure μ-agonist)
  • hydromorphone (Dilaudid)
  • oxymorphone (Opana)
  • methadone
  • meperedine (Demerol)
  • fentayl (Duragesic)

Moderate/Mild Agonists

  • codeine
  • oxycodone
  • hydrocodone
  • tramadol (Ultram)

Metabolism

  • PO dose is generally higher than the equivalent IV dose due to 1st pass effect (e.g. morphine, hydromorphone). PO dosing is also less predictable for the same reason.
  • codeine and oxycodone have little 1st pass metabolism.
  • opioids will accumulate in tissues in patients on frequent high dosing, or if lipophilic and slowly metabolized (fentanyl)
  • morphine is metabolized to
    • M6G (10%) - a potent analgesic
    • M3G - a neuroexcitatory compound; can cause seizures if accumulated (e.g. renal failure)
  • fentanyl has no active metabolites.