Seizures after pentazocine overdose.

A patient with seizures, coma and respiratory depression after pentazocine overdose was treated successfully with naloxone and artificial ventilation. Pentazocine is an antagonist of the mu opioid receptors and a partial agonist of the kappa and sigma receptors. Because naloxone has less affinity for kappa and sigma receptors than for mu receptors, larger doses of naloxone are frequently required in the treatment of pentazocine overdose. Our case lends support to the view that large doses of the narcotic antagonist naloxone may be effective in pentazocine overdose.