Heartburn and Stomach Medicines While Breastfeeding: Tums, Pepcid, Pepto-Bismol and More

Between night feeds, a hurried dinner and the stomach bug that goes around the house, it’s no surprise that nursing parents reach for the medicine cabinet. Most of what’s in there is fine. A few products deserve a closer look, and one of them, Pepto-Bismol, is where the sources we read are most cautious.

This guide goes through the common heartburn, indigestion, diarrhea and gas medicines, what LactMed and the NHS say about each, and when a stomach symptom needs a doctor instead of a pill. It’s general information, so check your own medicine and your baby’s situation with a doctor or pharmacist. The bigger picture is in our hub on what’s safe while breastfeeding.

At a glance

Medicine (examples)	Active ingredient	What the sources say
Tums, Gaviscon, magnesium antacids	Calcium carbonate, alginates, aluminum or magnesium salts	Acceptable; no special precautions (LactMed, NHS SPS)
Pepcid	Famotidine	Not expected to cause adverse effects in babies (LactMed)
Prilosec	Omeprazole	Low milk levels; not expected to cause adverse effects (LactMed)
Imodium	Loperamide	Minimal amounts in milk; standard doses unlikely to affect baby (LactMed)
Gas-X	Simethicone	Not absorbed, so cannot transfer to milk (LactMed)
Pepto-Bismol	Bismuth subsalicylate	Alternatives preferred because of salicylate (LactMed)

Heartburn: start with antacids

A review of heartburn in pregnancy and lactation found that most symptoms of pregnancy-related reflux ease during lactation, and that treatment moves in steps: lifestyle changes first, then antacids and alginates, then acid-reducing drugs if needed. The NHS Specialist Pharmacy Service (SPS) describes the same order.

Antacids: Tums and similar products

LactMed found no published data on the aluminum, calcium or magnesium content of milk during antacid use, but reasons that the extra minerals are unlikely to exceed what a baby gets from other foods, and that aluminum and magnesium are poorly absorbed. Reviewers generally consider antacids acceptable, with no special precautions.

SPS lists aluminum hydroxide, calcium carbonate, magnesium salts, simeticone and sodium bicarbonate as preferred choices and says no specific infant monitoring is usually needed. It also notes that bicarbonate does not accumulate in breast milk. The NHS says you can take Gaviscon while breastfeeding.

Read the label on combined products. The Tums Ultra label lists calcium carbonate 1000 mg per tablet, warns that antacids may interact with prescription drugs, and says not to use the maximum dosage for more than 2 weeks except under a doctor’s supervision. Some products, such as Pepcid Complete, combine an antacid with famotidine.

Famotidine (Pepcid) and other acid reducers

If antacids aren’t enough, LactMed says famotidine passes into milk at doses lower than those given to newborns and would not be expected to cause adverse effects. SPS prefers famotidine (or nizatidine) among the H2 blockers and says to watch your baby for diarrhea, constipation, irritability, drowsiness or rash. MotherToBaby agrees that famotidine gets into milk in small amounts and isn’t expected to cause problems.

SPS ranks cimetidine as the least preferred H2 blocker because of higher milk levels and interactions. LactMed says ranitidine can break down into a toxic compound if it isn’t formulated and stored properly, so an alternative may be preferred. If you have old ranitidine at home, ask your pharmacist what to use instead.

Omeprazole (Prilosec) and other proton pump inhibitors

LactMed says limited information shows that omeprazole 20 mg daily produces low milk levels and would not be expected to cause adverse effects. SPS says any PPI can be used, with omeprazole and pantoprazole preferred, and esomeprazole, lansoprazole and rabeprazole used with caution. The NHS says you can usually take omeprazole but to check with a pharmacist or doctor first.

The Prilosec OTC label is for frequent heartburn (2 or more days a week). It may take 1 to 4 days for full effect, and it says to stop and ask a doctor if you need it for more than 14 days. So it isn’t a quick fix for an occasional burn.

Pepto-Bismol and salicylate

Pepto-Bismol contains bismuth subsalicylate, a salicylate (the same family as aspirin). This is the product the sources are most cautious about.

• LactMed: its summary says that because the infant could absorb salicylate from breast milk, alternate therapies are preferred.
• The label: on the Pepto-Bismol suspension label we opened, each 30 mL dose contains 525 mg of bismuth subsalicylate and 261 mg of salicylate. The label says “If pregnant or breast-feeding, ask a health professional before use,” and carries a Reye’s syndrome warning for children and teenagers with chickenpox or flu-like symptoms.
• Aspirin as a comparison: LactMed’s aspirin entry says salicylic acid reaches milk, that higher doses give disproportionately higher milk levels, and that long-term high-dose maternal aspirin probably caused metabolic acidosis in one breastfed infant. It says the risk of Reye’s syndrome from salicylate in milk is unknown.

What we couldn’t find is a study measuring how much salicylate gets into milk after Pepto-Bismol, so we can’t tell you how much is “safe.” Given that, the practical route is to ask your pharmacist or doctor first and consider alternatives: an antacid for heartburn, or loperamide for diarrhea. The label also says a temporary, harmless darkening of the stool or tongue may occur.

Diarrhea: loperamide (Imodium)

LactMed says the amount of loperamide that enters milk is minimal and that standard doses are unlikely to affect your baby. The NHS says it’s OK to take and not expected to cause side effects, and suggests checking with a health professional if your baby isn’t feeding as well as usual, seems constipated or seems irritable.

The Imodium A-D label carries a heart warning: taking more than directed can cause serious heart problems. It also says not to use it with bloody or black stool, to ask a doctor if you have a fever or mucus in the stool, and to stop and ask a doctor if diarrhea lasts more than 2 days. If it’s a stomach bug, our guide to breastfeeding while sick has more.

Gas: simethicone (Gas-X)

LactMed says simethicone isn’t absorbed orally, so it can’t transfer to breast milk, and that it’s given directly to infants. No special precautions are needed.

When to call a doctor or your baby’s doctor

See a doctor promptly if you have trouble or pain swallowing, vomit blood, have bloody or black stools, or chest pain with shortness of breath, sweating, or pain spreading to your arms, neck or shoulders. These are warning signs listed on the heartburn medicine labels. Chest pain with those symptoms can be an emergency, so call 911 rather than waiting for an appointment. See one too if heartburn lasts more than 3 months, or keeps coming back despite treatment.

Contact your baby’s doctor if your baby has changes in stool, vomiting, constipation, poor sleeping, unusual drowsiness, irritability, a rash or feeds less well than usual. Our baby poop color chart shows what’s typical. For pain relievers, see ibuprofen and Tylenol while breastfeeding. If you’re unsure about a medicine or your supply changes, a pharmacist or IBCLC can help; our breastfeeding support page lists where to find one.