Skip to main content

Adefovir Pregnancy and Breastfeeding Warnings

Medically reviewed by Last updated on Feb 16, 2023.

Adefovir is also known as: Hepsera

Adefovir Pregnancy Warnings

Animal studies have failed to reveal evidence of embryotoxicity or teratogenicity using oral doses that produced systemic exposures at least 23 times (rats) and 40 times (rabbits) the human exposure at the therapeutic dose. Embryotoxicity and increased incidence of fetal malformations (anasarca, depressed eye bulge, umbilical hernia, kinked tail) were observed when pregnant rats were administered IV doses that produced exposures at least 38 times the human therapeutic exposure; such effects were not seen after an IV dose with an exposure 12 times the human therapeutic exposure. There are no controlled data in human pregnancy.

To monitor fetal outcomes of pregnant women exposed to this drug, a pregnancy registry has been established. Healthcare providers are encouraged to prospectively register patients. For additional information:

AU TGA pregnancy category B3: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have shown evidence of an increased occurrence of fetal damage, the significance of which is considered uncertain in humans.

US FDA pregnancy category C: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

This drug should be used during pregnancy only if clearly needed and the benefit outweighs the risk to the fetus.

AU TGA pregnancy category: B3
US FDA pregnancy category: C

-There are no data concerning the effect of this drug on mother-to-infant hepatitis B virus (HBV) transmission; appropriate infant immunization recommended to prevent neonatal acquisition of HBV.
-According to some authorities, effective contraception must be used during therapy; this drug is not recommended during pregnancy or in females of reproductive potential not using contraception.

See references

Adefovir Breastfeeding Warnings

LactMed: An alternative agent may be preferred, particularly while breastfeeding newborn or preterm infants.
-According to some authorities: Breastfeeding is not recommended during use of this drug.
-According to some authorities: A decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother.

Excreted into human milk: Unknown
Excreted into animal milk: Data not available

-This drug has not been studied in nursing mothers receiving treatment for hepatitis B virus infection.

See references

References for pregnancy information

  1. "Product Information. Hepsera (adefovir)." Gilead Sciences (2022):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. TGA. Therapeutic Goods Administration. Australian Drug Evaluation Committee "Prescribing medicines in pregnancy: an Australian categorisation of risk of drug use in pregancy." (2007):
  4. Cerner Multum, Inc. "Australian Product Information." O 0

References for breastfeeding information

  1. "Product Information. Hepsera (adefovir)." Gilead Sciences (2022):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Cerner Multum, Inc. "Australian Product Information." O 0
  4. United States National Library of Medicine "Toxnet. Toxicology Data Network." (2013):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.