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Alendronate Pregnancy and Breastfeeding Warnings

Medically reviewed by Last updated on Oct 10, 2022.

Alendronate is also known as: Binosto, Fosamax

Alendronate Pregnancy Warnings

In rats, oral administration before mating through the end of gestation or lactation showed decreased postimplantation survival and decreased pup weight gain at doses estimated to be less than 50% of the recommended human dose. Reduced fetal ossification was observed in rats dosed during organogenesis at doses approximately 3 times the recommended human dose; delayed or failed offspring delivery, protracted birth, and late pregnancy maternal and fetal deaths due to maternal hypocalcemia occurred at doses as low as one-tenth the recommended human dose. In humans, bisphosphonates are incorporated into the bone matrix and gradually release over a period of years; the amount available for release into the systemic circulation is directly related to the dose and duration of bisphosphonate use. The risk of pregnancy following bisphosphonate therapy has not been studied, however, due to the mechanism of action of bisphosphonates, there is a potential risk of fetal harm if a woman becomes pregnant following bisphosphonate therapy. There are no controlled data in human pregnancy.

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 Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

Not Recommended

AU TGA pregnancy category: B3
US FDA pregnancy category: Not available

Risk Summary: Data is insufficient to inform a drug-associated risk of maternal or fetal outcomes; animal studies have shown reproductive toxicity.

Comment: Discontinue when pregnancy is recognized.

See references

Alendronate Breastfeeding Warnings

Benefit should outweigh risk

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

-There are no data on the effects of this drug on the breastfed infant or its effects on milk production.
-The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for this drug and any potential adverse effects to the breastfed infant from the drug or from the underlying maternal condition.

This drug is poorly orally absorbed in adults with the average absorption estimated at 1%. Because it is poorly absorbed, absorption by a breast fed infant is unlikely. Limited evidence suggests that breastfeeding after cessation of long-term bisphosphonate therapy appears to have no adverse effects on the infant. Some authorities advise against breastfeeding as it has not been studied.

See references

References for pregnancy information

  1. "Product Information. Fosamax (alendronate)." Merck & Co., Inc (2001):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Cerner Multum, Inc. "Australian Product Information." O 0

References for breastfeeding information

  1. "Product Information. Fosamax (alendronate)." Merck & Co., Inc (2001):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Cerner Multum, Inc. "Australian Product Information." O 0

Further information

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