Key takeaways
Famotidine (Pepcid AC) and bismuth subsalicylate (Pepto-Bismol) are both used to treat stomach-related issues, but they work differently and are used for different conditions. Famotidine is a histamine-2 (H2) antagonist that reduces stomach acid and is used for heartburn, stomach ulcers, and conditions like GERD. It is available both over-the-counter and by prescription. On the other hand, bismuth subsalicylate is an antidiarrheal that treats diarrhea and symptoms of an upset stomach, such as nausea and gas. It is only available over-the-counter. Famotidine is typically taken twice a day, while bismuth subsalicylate can be taken every 30 minutes to an hour as needed. Famotidine can cause headaches and dizziness, whereas bismuth subsalicylate can cause dark-colored stools and a dark tongue. Additionally, bismuth subsalicylate should not be used by children under 12, while famotidine can be used in younger children under medical guidance.
