21. "' Allylprodine "'is an opioid analgesic that is an analog of prodine. 22. "' Prosidol "'is an opioid analgesic that is an analogue of prodine. 23. It is one of the most effective orally-administered opioid analgesics and has a wide safety margin. 24. "' 3-Acetyloxymorphone "'is an opioid analgesic which has never been marketed. 25. "' Clonitazene "'is an opioid analgesic of approximately three times the potency of morphine. 26. "' Cyclorphan "'is an opioid analgesic of the morphinan family that was never marketed. 27. "' Norlevorphanol "'is an opioid analgesic of the morphinan family that was never marketed. 28. "' 4-Phenylfentanyl "'is an opioid analgesic that is a derivative of fentanyl. 29. "' Volazocine "'is an opioid analgesic of the benzomorphan class which was never marketed. 30. "' Carbazocine "'is an opioid analgesic of the benzomorphan family which was never marketed.
