Pentamorphone (14β-pentylaminomorphinone, RX-77989) is a semi-synthetic opiate derivative related to compounds such as morphine, hydromorphone and oxymorphone. Developed in 1984, it is a potent opioid analgesic several times stronger than fentanyl, and with a similarly fast onset of effects and short duration of action. It was found to produce relatively little respiratory depression compared to other potent opioid agonists, but its analgesic effects were somewhat disappointing in human trials, and while pentamorphone had some slight advantages over fentanyl these were not sufficient to warrant its introduction into clinical use.
^Glass PS, Camporesi EM, Shafron D, Quill T, Reves JG. Evaluation of pentamorphone in humans: a new potent opiate. Anesthesia and Analgesia. 1989 Mar;68(3):302-7. PMID2465708
^Rudo FG, Wynn RL, Ossipov M, Ford RD, Kutcher BA, Carter A, Spaulding TC. Antinociceptive activity of pentamorphone, a 14-beta-aminomorphinone derivative, compared to fentanyl and morphine. Anesthesia and Analgesia. 1989 Oct;69(4):450-6. PMID2476953
^Afifi MS, Glass PS, Cohen NA, Shook JE, Camporesi EM. Depression of ventilatory responses to hypoxia and hypercapnia after pentamorphone. Anesthesia and Analgesia. 1990 Oct;71(4):377-83. PMID1698039
^Wong HY, Parker RK, Fragen R, White PF. Pentamorphone for management of postoperative pain. Anesthesia and Analgesia. 1991 May;72(5):656-60. PMID1708214
^Kelly WB, Howie MB, Romanelli VA, Duarte JA, Rezaei H, McSweeney TD. A comparison of pentamorphone and fentanyl in balanced anaesthesia during general surgery. Canadian Journal of Anesthesia. 1994 Aug;41(8):703-9. PMID7522977