PENICILLIN G, BENZATHINE

Fetal Risk Summary

Benzathine penicillin G is a combination of an ammonium base and penicillin G suspended in water (see also Penicillin G). Reproduction studies in mice, rats and rabbits have revealed no evidence of impaired fertility or fetal harm (1).

The pharmacokinetics of benzathine penicillin G in healthy women at 38–39 weeks' gestation, 1–7 days before delivery, have been described (2). Penicillin concentrations were measured in maternal serum, maternal cerebrospinal fluid, cord serum, and amniotic fluid. Because of the wide range of concentrations measured, the authors concluded that the altered pharmacokinetics occurring at this time may adversely affect the efficacy of the drug to prevent congenital syphilis.

Breast Feeding Summary

See Penicillin G.

References

1. Product information. Bicillin L-A. Wyeth-Ayerst Pharmaceuticals, 2000.
2. Nathan L, Bawdon RE, Sidawi JE, Stettler RW, McIntire DM, Wendel GD Jr. Penicillin levels following the administration of benzathine penicillin G in pregnancy. Obstet Gynecol 1993;82:338–42.