PHENAZOCINE

Fetal Risk Summary

No reports linking the use of phenazocine with congenital defects in humans have been located. In a reproductive study with hamsters, increasing doses (100–240 mg/kg) administered as single SC injections during the critical period of central nervous system organogenesis resulted in a significant increase in malformations (exencephaly and cranioschisis) in the offspring (1). Maternal mortality was not observed at the doses tested.

Phenazocine is not commercially available in the United States. Withdrawal could theoretically occur in infants exposed in utero to prolonged maternal ingestion of phenazocine. Phenazocine may cause neonatal respiratory depression when used in labor (2,3).

[*Risk Factor D if used for prolonged period or in high doses at term.]

Breast Feeding Summary

No data are available.

References

1. Geber WF, Schramm LC. Congenital malformations of the central nervous system produced by narcotic analgesics in the hamster. Am J Obstet Gynecol 1975;123:705–13.
2. Sadove M, Balagot R, Branion J Jr, Kobak A. Report on the use of a new agent, phenazocine, in obstetric analgesia. Obstet Gynecol 1960;16:448–53.
3. Corbit J, First S. Clinical comparison of phenazocine and meperidine in obstetric analgesia. Obstet Gynecol 1961;18:488–91.