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Cimetidine Pregnancy and Breastfeeding Warnings

Cimetidine is also known as: Acid Reducer-Cimetidine, Equaline Acid Reducer, Leader Heartburn Relief, Tagamet, Tagamet HB

Medically reviewed by Last updated on May 29, 2019.

Cimetidine Pregnancy Warnings

Use is recommended only if clearly needed and the benefit outweighs the risk.

AU TGA pregnancy category: B1
US FDA pregnancy category: B

Animal studies have failed to reveal evidence of fetal harm, impaired fertility, or mating performance at doses 8 to 48 times the full therapeutic dose. In humans, this drug was shown to not influence spermatogenesis, sperm count, motility, morphology, or in vitro fertilizing capacity.

AU TGA pregnancy category B1: 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 not shown evidence of an increased occurrence of fetal damage.

US FDA pregnancy category B: Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women.

See references

Cimetidine Breastfeeding Warnings

Use in nonlactating patients may increase prolactin secretion, which may result in gynecomastia and/or galactorrhea.

Fully breastfed infant exposure is predicted to be between 0.74 to 0.9 mg/kg/day, significantly less than the 5 to 10 mg/kg/day doses given directly to neonates.

Breastfeeding is not recommended during use of this drug.

Excreted into human milk: Yes

-The effects of this drug in the nursing infant are unknown.
-The American Academy of Pediatrics considers this drug compatible with breastfeeding.
-The WHO recommends that this drug should be avoided if possible, as there are insufficient data on long-term side effects.
-Some experts state this drug has the potential for causing liver enzyme inhibition; other drugs (e.g., famotidine, nizatidine, omeprazole, pantoprazole, ranitidine, sucralfate) may be preferred, especially in patients younger than 2 months.

See references

References for pregnancy information

  1. TGA. Therapeutic Goods Administration. Australian Drug Evaluation Committee "Prescribing medicines in pregnancy: an Australian categorisation of risk of drug use in pregnancy. Available from: URL:" ([1999]):
  2. Cerner Multum, Inc. "Australian Product Information." O 0
  3. "Product Information. Tagamet HB (cimetidine)." SmithKline Beecham, Philadelphia, PA.
  4. "Product Information. Tagamet (cimetidine)." SmithKline Beecham, Philadelphia, PA.
  5. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

References for breastfeeding information

  1. "Product Information. Tagamet (cimetidine)." SmithKline Beecham, Philadelphia, PA.
  2. "Product Information. Tagamet HB (cimetidine)." SmithKline Beecham, Philadelphia, PA.
  3. Briggs GG, Freeman RK. "Drugs in Pregnancy and Lactation. 10th ed." Philadelphia, PA: Wolters Kluwer Health (2015):
  4. Department of Adolescent and Child Health and Development. UNICEF. World Health Organization "Breastfeeding and maternal medication: recommendations for drugs in the eleventh Who model list of essential drugs. Available from: URL:" ([2003]):
  5. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  6. 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.