Can you take Tums and Pepcid together?
For most healthy adults these two are generally fine together and are even sold pre-combined, but check the label timing and ask a pharmacist if you take other medicines, are pregnant, or have kidney problems.
Why
They work by different mechanisms, so there is no duplicate active ingredient to double up on. Tums is calcium carbonate, an antacid that neutralizes acid already in your stomach (MedlinePlus). Pepcid is famotidine, an H2 blocker that "decreases the amount of acid made in the stomach" (MedlinePlus). Because the actions differ and don't overlap, the FDA-approved product Pepcid Complete deliberately combines both — famotidine plus calcium carbonate plus magnesium hydroxide — for fast plus longer relief (MedlinePlus famotidine page), which is direct evidence the pairing is an accepted combination.
What to watch for
Two practical points from the labels. First, timing with OTHER drugs: MedlinePlus advises not taking calcium carbonate within 1-2 hours of other medicines because calcium can reduce their absorption — so if you're on other prescriptions, separate them from the Tums, not necessarily from the Pepcid. Second, don't add a new heartburn medicine on top without checking: the famotidine label says do not start other heartburn medications while taking it without discussing with your provider. Follow each product's Drug Facts dose limits and don't exceed the daily maximum on either. Ask a pharmacist or doctor first if you take other prescription drugs, have kidney disease (calcium and famotidine both need caution there), are pregnant or breastfeeding, or if heartburn lasts more than 2 weeks — that warrants a medical look, not more OTC dosing.
This is general reference, not medical advice, and not a guarantee of safety. Interactions depend on your doses, health conditions, and other medicines. Always confirm with your pharmacist or doctor before combining products, and follow the dosing on each label.