Oxymorphone is a potent semisynthetic OPIOID ANALGESIC derived from thebaine, one of the twenty ALKALOIDS occurring naturally in OPIUM. It is approximately fivefold more potent than MORPHINE and has very similar actions and side effects. It is used to treat moderate to severe PAIN. Oral formulations are not available in the United States, but it is available by injection or by rectal suppository. Like morphine, continued use of oxymorphone leads to TOLERANCE AND PHYSICAL DEPENDENCE. It is interesting that oxymorphone shares the same basic chemical structure as the ANTAGONISTS NALOXONE and NALTREXONE, the only difference being the substituent on the nitrogen. Neither naloxone nor naltrexone have analgesic activity; in contrast to oxymor-phone, they are instead capable of blocking opiate actions.

Figure 1 Oxymorphone

Bibliography

JAFFE, J. H., & MARTIN, W. R. (1990). Opioid analgesics and antagonists. In A. G. Gilman et al. (Eds.), Goodman and Gilman's the pharmacological basis of therapeutics, 8th ed. New York: Pergamon.