Narcotic Agonist Analgesic
PREGNANCY RECOMMENDATION: Human Data Suggest Risk
BREASTFEEDING RECOMMENDATION: No Human Data—Potential Toxicity
PREGNANCY SUMMARY
Although oxymorphone was not included in a National Birth Defects Prevention Study, the use of other opioid agonists during organogenesis was associated with a low absolute risk of congenital birth defects (see Morphine). In addition, the use of any opioid agonist during labor or close to delivery may cause neonatal respiratory depression.
FETAL RISK SUMMARY
Oxymorphone is an opioid agonist that is available in both oral and injectable formulations. It is highly metabolized in the liver to active and inactive metabolites (1).
Reproduction studies have been conducted in rats, rabbits, and hamsters. Oxymorphone did not cause malformations in rats and rabbits at daily oral doses that were about 2 and 8 times, respectively, the total human daily oral dose of 120 mg based on BSA (THDD). Fetal weights were decreased in both species at doses that were about 0.8 and 4 times the THDD. In rats given the drug daily during gestation and postnatally at a dose that was about 2 times the THDD, there was an increase in stillborn pups and neonatal deaths, as well as low pup birth weight and a decrease in postnatal weight gain. In hamsters, a single SC dose that was about 10 times the THDD produced malformations in offspring but also produced 83% maternal death (1).
Although no studies have been found indicating that oxymorphone crosses the human placenta, the molecular weight (about 338) and experience with other opioid analgesics (e.g., see Morphine) indicates that the drug will rapidly cross to the embryo–fetus.
Use of oxymorphone during labor produces neonatal respiratory depression to the same degree as other narcotic analgesics (2–5).
BREASTFEEDING SUMMARY
No reports describing the use of oxymorphone during human lactation have been located. However, the molecular weight (about 338) and experience with other opioid analgesics (e.g., see Morphine) indicates that the drug will be excreted into breast milk. Although occasional maternal doses would probably not produce adverse effects in the nursing infant, higher doses and prolonged use could cause toxicity. Moreover, long-term effects on neurobehavior and development are unknown but warrant study.
References
1.Product information. Opana. Endo Pharmaceuticals, 2013.
2.Simeckova M, Shaw W, Pool E, Nichols EE. Numorphan in labor. A preliminary report. Obstet Gynecol 1960;16:119–23.
3.Sentnor MH, Solomons E, Kohl SG. An evaluation of oxymorphone in labor. Am J Obstet Gynecol 1962;84:956–61.
4.Eames GM, Pool KRS. Clinical trial of oxymorphone in labor. Br Med J 1964; 2:353–5.
5.Ransom S. Oxymorphone as an obstetric analgesic. A clinical trial. Anesthesia 1966;21:464–71.