TOPICS: Pentazocine, butorphanol, full agonists at kappa opioid receptors, partial agonists at mu opioid receptors, nalbuphine, full kappa agonist, partial mu antagonist, moderate to severe pain, labor and delivery pain, less respiratory depression, mixed agonist/antagonist can precipitate immediate withdrawal, irritability, anger, abdominal pain, anxiety, nausea, vomiting, not easily reversed with naloxone
