Agonist/Antagonist Opioid Analgesics. When a affected person has previously received or is presently undergoing a training course of therapy with a pure opioid agonist analgesic like Dilaudid, agonist/antagonist analgesics like pentazocine, nalbuphine, butorphanol, and buprenorphine, ought to be used with caution.Respiratory depression. Respirato