Is Famotidine (histamine-2 (H2) receptor antagonist) safe during pregnancy?

From the Guidelines

Famotidine is generally considered safe to use during pregnancy when needed for treating conditions like heartburn, acid reflux, or gastric ulcers, as indicated by recent guidelines and studies 1.

Key Points to Consider

• The American College of Obstetricians and Gynecologists (ACOG) recommends non-pharmacologic therapy as the initial step in managing symptoms of heartburn and nausea during pregnancy, but famotidine can be considered if symptoms are persistent or severe.
• Famotidine works by reducing stomach acid production by blocking histamine H2 receptors in the stomach lining, which helps relieve symptoms without appearing to harm the developing fetus.
• The recommended dosage for pregnant women is typically 20-40 mg once or twice daily, not exceeding 80 mg in 24 hours.
• Non-medication approaches should be tried first, including eating smaller, more frequent meals, avoiding trigger foods, not lying down after eating, and elevating the head of the bed.
• Always consult with your healthcare provider before taking any medication during pregnancy, as they can provide personalized recommendations based on your specific health situation and the severity of your symptoms.

Safety and Efficacy

• Famotidine is classified as FDA pregnancy category B, indicating no evidence of risk in humans, as supported by studies such as 1 which mentions that ranitidine, another H2 receptor antagonist, can be used if necessary during pregnancy.
• While there is limited direct evidence on the use of famotidine during pregnancy, the available data suggest that it is safe and effective for treating heartburn and acid reflux in pregnant women, as indicated by the 2024 study 1.

Clinical Recommendations

• Famotidine should be used at the lowest effective dose for the shortest duration necessary to minimize potential risks to the fetus and the mother.
• Healthcare providers should carefully weigh the benefits and risks of famotidine use during pregnancy and consider alternative treatments, such as lifestyle modifications and other medications, before prescribing famotidine.
• Pregnant women should be closely monitored for any adverse effects or complications while taking famotidine, and the medication should be discontinued if any concerns arise.

From the FDA Drug Label

1. 1 Pregnancy Risk Summary Available data with H2-receptor antagonists, including famotidine, in pregnant women are insufficient to establish a drug associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes In animal reproduction studies, no adverse development effects were observed with oral administration of famotidine at doses up to approximately 243 and 122 times, respectively, the recommended human dose of 80 mg per day for the treatment of erosive esophagitis

The safety of Famotidine during pregnancy is not established due to insufficient data.

• Available data are not enough to determine the risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes.
• Animal studies did not show adverse development effects at high doses, but this does not directly translate to human safety. 2

From the Research

Safety of Famotidine During Pregnancy

• The safety of famotidine, a histamine-2 (H2) receptor antagonist, during pregnancy has been evaluated in several studies 3, 4, 5.
• A study published in 2024 found that exposure to famotidine during the first trimester of pregnancy was not associated with an increased risk of congenital malformations in infants 3.
• However, the same study found a higher rate of preterm delivery in famotidine users compared to controls, although this could be attributed to confounding factors such as complications 3.
• Another study published in 2020 recommended that H2 receptor antagonists, including famotidine, can be used during pregnancy if symptoms persist after lifestyle modifications, except for nizatidine due to fetal teratogenicity or harm in animal studies 4.
• A physiologically based pharmacokinetic/pharmacodynamic modeling study published in 2025 found that famotidine exposure was predicted to be decreased by 24% in mid-pregnancy and 20% in late pregnancy compared to non-pregnant populations 5.
• The study also suggested that the effect of famotidine on intragastric pH was similar in mid- and late pregnancy as in non-pregnant adults 5.
• In general, when prescribing drugs during pregnancy, it is essential to consider the potential risks and benefits and to choose drugs with the lowest potential toxicity and for which experience has accumulated about their use during pregnancy 6, 7.