Amoxicillin does not have an FDA-approved indication for anthrax prophylaxis or treatment, however, if the strain of Bacillus anthracis is penicillin-susceptible, prophylactic therapy with amoxicillin may be considered according to the CDC.1 In pregnant and lactating women, the FDA recommends 1000 mg amoxicillin every eight hours.
In 2012, the Centers for Disease Control and Prevention (CDC) partnered with the Association of Maternal and Child Health Programs to discuss the prevention and treatment of anthrax in pregnant, postpartum and lactating women.1,2 Upon conclusion of the meeting, a new technical document was published that supersedes the previous CDC guidelines for the prevention and treatment of anthrax in pregnant, postpartum and lactating women and aligns with updated recommendations in adults that are not pregnant.1 According to data in published literature, high rates of maternal and fetal death have been reported in pregnant and postpartum women exposed to Bacillus anthracis.3
CDC guidelines for prophylaxis and treatment of anthrax in pregnant and postpartum women are available at https://wwwnc.cdc.gov/eid/article/20/2/13-0611-techapp1.pdf. According to the CDC, ciprofloxacin (500 mg, orally, every 12 hours for 60 days) is the preferred treatment for prophylaxis of inhalational anthrax in asymptomatic pregnant and lactating women exposed to Bacillus anthracis.2 If ciprofloxacin is not available or not tolerated, CDC provides recommendations for use of other antibacterial drugs for prophylaxis of inhalational anthrax, such as doxycycline (100 mg every 12 hours). If the strain of Bacillus anthracis is penicillin-susceptible, prophylactic therapy with amoxicillin may be considered according to the CDC.1
General Background on Amoxicillin and Penicillins:
Penicillins, as a drug class, are generally considered acceptable for use in pregnancy and are used in the treatment of various infections in pregnant women. Published clinical studies evaluating the use of amoxicillin in pregnant women have not identified an association with amoxicillin exposure during pregnancy and major birth defects, miscarriage or adverse maternal or fetal outcomes. 4,5,6,7,8,9,10,11,12,13,14,15,16
According to published literature, amoxicillin is present in breast milk in low levels. The relative infant dose (RID) range for amoxicillin has been calculated to be approximately 1%. Amoxicillin is not expected to cause adverse reactions in breastfed infants. The RID gives an estimate of the amount of the maternal dose received by the infant. A drug with a RID less than 10% is considered to be compatible with breastfeeding.17,18,19,20,21,22,23,24,25
1Meaney-Delman D., M.E. Zotti, A.A. Creanga, et al., “Special Considerations for Prophylaxis for and Treatment of Anthrax in Pregnant and Postpartum Women,” Emerging Infectious Diseases, vol. 20(2), 2014 (available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3901460/.
2CDC, “Special Considerations for Prophylaxis for and Treatment of Anthrax in Pregnant and Postpartum Women: Technical Appendix,” 2014 (available at https://wwwnc.cdc.gov/eid/article/20/2/13-0611-techapp1.pdf).
3Meaney-Delman D., Et al., “Anthrax Cases in Pregnant and Postpartum Women: A Systematic Review.” Obstetrics & Gynecology, vol. 120(6), pp. 1439-49, 2012.
7Almeida L., A. Schmauch, and S.A. Bergstrom, ”Randomized Study on the Impact of Perioral Amoxicillin in Women With Pre-Labour Rupture of Membranes Preterm,” Gynecologic and Obstetrics Investigation, vol. 41,pp.82-84, 1996.
8Lovett S.M., J.D. Weiss, M.J. Diogo, et al., “A Prospective, Double-Blind, Randomized, Controlled Clinical Trial of Ampicillin-Sulbactam for Preterm Premature Rupture of Membranes in Women Receiving Antenatal Corticoid Therapy,” American Journal of Obstetrics Gynecology, vol. 176, pp. 1030-1038, 1997.
9Mercer B.M., M. Miodovnik, G.R. Thurmau., et al., “Antibiotic Therapy For Reduction of Infant Morbidity After Preterm Premature Rupture of the Membranes. A Randomized Controlled Trial,” The Journal of the American Medical Association, vol. 278, pp. 989-995 1997.
10Czeizel A.E., M. Rockenbauer,H.T. Sorensen, et al., “Augmentin Treatment During Pregnancy and the Prevalence of Congenital Abnormalities: A Population-Based Case-Control Teratologic Study,” European Journal of Obstetrics & Gynecology and Reproductive Biology, vol. 97, pp. 188-192, 2001.
15Cooper W.O., S. Hernandez-Diaz, P.G. Arbogast, et al., “Antibiotics Potentially Used in Response to Bioterrorism and the Risk of Major Congenital Malformations,” Paediatric Perinatal Epidemiology,vol. 23 (1),pp 18-28, 2009.
16Jepsen P., M.V. Skriver, A. Floyd, et al., “A Population-Based Study of Maternal Use of Amoxicillin and Pregnancy Outcome in Denmark,” British Journal of Clinical Pharmacology, vol. 55(2), pp. 216-21, 2003.
20Ito S., A.M. Blajchman, M. M. Stephenson, et al., “Prospective Follow-Up of Adverse Reactions in Breast-Fed Infants Exposed to Maternal Medication,” American Journal of Obstretics & Gynecology, vol. 168, pp. 1393-1399, 1993.
21Campbell A.C., J.C. McElnay, C.M. Passmore, “The Excretion of Ampicillin in Breast Milk and Its Effect on the Suckling Infant,” British Journal of Clinical Pharmacology. vol. 31, p. 230 Abstract, 1991.