PROMAZINE

Fetal Risk Summary

Promazine is a propylamino phenothiazine structurally related to chlorpromazine. The drug readily crosses the placenta (1,2).

The Collaborative Perinatal Project monitored 50,282 mother-child pairs, 50 of which had 1st trimester exposure to promazine (3). For use anytime during pregnancy, 347 exposures were recorded. No evidence was found in either group to suggest a relationship to malformations or an effect on perinatal mortality rate, birth weight, or intelligence quotient scores at 4 years of age.

A possible relationship between the use of promazine (100 mg or more) in labor and neonatal hyperbilirubinemia was reported in 1975 (4). In addition, a study published in 1980 found that the administration of promazine close to delivery caused a reduction in neonatal platelet aggregation (5). The clinical significance of this effect is unknown.

Although occasional reports have attempted to link various phenothiazine compounds with congenital defects, the bulk of the evidence indicates that these drugs are safe for mother and fetus (see also Chlorpromazine).

Breast Feeding Summary

No reports describing the use of promazine during human lactation have been located. Because the agent readily crosses the placenta, excretion into breast milk should be expected. The effects, if any, on a nursing infant are unknown, but sedation is a possibility.

References

1. Moya F, Thorndike V. Passage of drugs across the placenta. Am J Obstet Gynecol 1962;84:1778–98.
2. O'Donoghue SEF. Distribution of pethidine and chlorpromazine in maternal, foetal and neonatal biological fluids. Nature 1971;229:124–5.
3. Slone D, Siskind V, Heinonen OP, Monson RR, Kaufman DW, Shapiro S. Antenatal exposure to the phenothiazines in relation to congenital malformations, perinatal mortality rate, birth weight, and intelligence quotient score. Am J Obstet Gynecol 1977;128:486–8.
4. John E. Promazine and neonatal hyperbilirubinemia. Med J Aust 1975;2:342–4.
5. Whaun JM, Smith GR, Sochor VA. Effect of prenatal drug administration on maternal and neonatal platelet aggregation and PF4 release. Haemostasis 1980;9:226–37.