From the Guidelines
Famotidine is the preferred first-line treatment for acid-related disorders during pregnancy due to its longer safety record and FDA Pregnancy Category B classification. Both famotidine and omeprazole are considered acceptable options, but famotidine is often chosen as the initial therapy, especially in early pregnancy 1. The typical dosage of famotidine is 20-40 mg once or twice daily. Omeprazole, classified as FDA Pregnancy Category C, is usually reserved for women who don't respond adequately to famotidine or other H2 blockers, with a standard dose of 20-40 mg once daily.
When treating acid-related disorders in pregnancy, it's best to start with lifestyle modifications (avoiding trigger foods, eating smaller meals, not lying down after eating) and antacids before progressing to famotidine. If symptoms persist or are severe, omeprazole may be used, particularly in the second and third trimesters when the benefit typically outweighs potential risks. Key considerations include:
- Famotidine's mechanism of blocking histamine receptors to reduce stomach acid production
- Omeprazole's more potent inhibition of the proton pump that produces acid, making it more effective but potentially carrying slightly more theoretical risk during pregnancy
- The importance of weighing the benefits and risks of each medication, as outlined in the study 1, which provides a framework for categorizing drugs during pregnancy, including the FDA categories and the concept of "compatible," "probably safe," "possibly safe," and breastfeeding considerations.
Given the available evidence, famotidine is the recommended initial treatment for acid-related disorders in pregnant women, with omeprazole considered for second-line use or in cases where famotidine is not effective 1.
From the FDA Drug Label
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 There are no adequate and well-controlled studies with omeprazole in pregnant women. Available epidemiologic data fail to demonstrate an increased risk of major congenital malformations or other adverse pregnancy outcomes with first trimester omeprazole use
Comparison of Famotidine and Omeprazole in Pregnancy
- Both famotidine and omeprazole have limited data on their use in pregnant women.
- Famotidine: Insufficient data to establish a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes 2.
- Omeprazole: No adequate and well-controlled studies, but available epidemiologic data do not demonstrate an increased risk of major congenital malformations or other adverse pregnancy outcomes with first trimester use 3 3.
- Key Consideration: The estimated background risks of major birth defects and miscarriage for the indicated population are unknown, but in the U.S. general population, the background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
- Clinical Decision: Given the limited data, it is essential to weigh the benefits and risks of using either medication during pregnancy and consider alternative treatments if possible.
From the Research
Comparison of Famotidine and Omeprazole in Pregnancy
- There is limited direct comparison between famotidine and omeprazole in pregnancy, but available data suggest that both can be used during pregnancy with caution 4, 5, 6, 7.
- Omeprazole is a proton pump inhibitor (PPI) that has been studied more extensively in pregnancy, and data suggest that it is not teratogenic in humans 4, 6.
- Famotidine is an H2 receptor antagonist (H2RA) that can be used in pregnancy, especially when combined with a PPI for better control of nocturnal gastric acid breakthrough (NAB) 8.
- The use of acid-suppressing drugs, including H2RAs like famotidine and PPIs like omeprazole, during the first trimester of pregnancy is not associated with a major teratogenic risk 7.
Safety of Proton Pump Inhibitors in Pregnancy
- A multicentre prospective controlled study found that the rate of major congenital anomalies did not differ between pregnant women exposed to omeprazole, lansoprazole, or pantoprazole and a control group 6.
- Another study found that the use of PPIs during pregnancy is not associated with an increased risk of congenital malformations, preterm delivery, or growth retardation 7.
Management of Heartburn during Pregnancy
- The management of heartburn during pregnancy begins with lifestyle modifications, and medical providers must discuss the risks and benefits of medicines with the patient in detail 5.
- Antacids, alginates, and sucralfate are the first-line therapeutic agents, and H2RAs like famotidine can be used if symptoms persist 5.
- PPIs like omeprazole are reserved for women with intractable symptoms or complicated gastroesophageal reflux disease (GERD) 5.