Agonist/Antagonist Opioid Analgesics. When a patient has Earlier acquired or is now undergoing a system of therapy with a pure opioid agonist analgesic like Dilaudid, agonist/antagonist analgesics like pentazocine, nalbuphine, butorphanol, and buprenorphine, need to be used with caution.The risk that you're going to build breathing challenges cou