Three types of over-the-counter medicine treat acid reflux, and each works differently. Antacids like Tums and Rolaids neutralize stomach acid that’s already there, giving you the fastest relief. H2 blockers like famotidine (Pepcid) reduce acid production for several hours. And proton pump inhibitors like omeprazole (Prilosec OTC) shut down acid production more completely but take days to reach full effect. The best choice depends on whether you need quick relief right now or want to prevent symptoms over days or weeks.
Antacids: Fastest Relief, Shortest Duration
Antacids are the simplest option and the one most people reach for first. They contain mineral salts, most commonly calcium carbonate (Tums, Rolaids), magnesium hydroxide (Milk of Magnesia), or a combination of magnesium and aluminum (Maalox, Mylanta). These ingredients chemically neutralize the acid already sitting in your stomach and esophagus.
Speed is their main advantage. Effervescent sodium bicarbonate formulas can start working in seconds. Chewable calcium carbonate tablets begin raising stomach pH within about 5 to 30 minutes, depending on the formulation. But the tradeoff is duration: taken on an empty stomach, antacids last only 20 to 60 minutes. Taken after a meal, a single dose can neutralize acid for up to two hours. Chewable tablets tend to last longer than swallowable ones, with stomach relief lasting roughly 100 to 180 minutes.
Antacids are best for occasional, predictable heartburn, like the burn you get after a heavy meal or spicy food. They’re not designed for daily use over long periods. If you find yourself reaching for them more than twice a week, a longer-acting option is worth considering.
H2 Blockers: Hours of Prevention
H2 blockers work by reducing the amount of acid your stomach produces in the first place. They block histamine signals to the acid-producing cells in your stomach lining, which lowers acid output for a longer window than antacids can manage. Famotidine (Pepcid AC) is the most widely available H2 blocker over the counter. It’s typically taken as a 20 mg tablet once or twice daily.
The key difference from antacids is timing. H2 blockers take 30 to 60 minutes to kick in, so they won’t rescue you from heartburn you’re feeling right now as quickly as a Tums will. But they provide several hours of reduced acid production, making them useful when you want to prevent symptoms before they start. Taking one 30 minutes before a meal you know will trigger reflux, or before bed if nighttime symptoms are your problem, is a common strategy. For ongoing reflux, the standard OTC approach is 20 mg twice a day for up to six weeks.
Proton Pump Inhibitors: Strongest Suppression
PPIs are the most powerful acid suppressors available without a prescription. Three are sold OTC: omeprazole (Prilosec OTC), lansoprazole (Prevacid 24HR), and esomeprazole (Nexium 24HR). They permanently disable the acid pumps in your stomach lining. Your body has to make new pumps to resume normal acid production, which is why the effect builds over several days and lingers after you stop.
This makes PPIs a poor choice for occasional heartburn. They’re designed for people who have frequent acid reflux, typically defined as two or more days per week. The OTC instructions call for one dose daily, taken before your first meal of the day, for a 14-day course. You shouldn’t repeat that course more than every four months unless directed by a doctor. Full relief often doesn’t arrive until day two or three, so pairing a PPI with antacids during the first few days is reasonable.
Long-Term PPI Risks
PPIs are safe for short courses, but extended use carries some well-documented concerns. The FDA issued a safety alert in 2010 linking long-term PPI use to an increased risk of hip, wrist, and spine fractures, likely because suppressing stomach acid reduces calcium absorption. Chronic use has also been associated with low magnesium levels, reduced iron absorption leading to anemia, and vitamin B12 deficiency, since stomach acid is needed to release B12 from food. None of this means a 14-day OTC course is dangerous. It means that if you find yourself needing PPIs repeatedly, that’s a conversation worth having with a doctor rather than just cycling through OTC boxes indefinitely.
Alginate Products: A Physical Barrier
Alginate-based products like Gaviscon work through a completely different mechanism. When sodium alginate hits stomach acid, it forms a gel. Bicarbonate in the formula reacts with the acid to produce carbon dioxide bubbles, which get trapped in the gel and cause it to float on top of your stomach contents like a raft. This physical barrier sits between the acid pool and your esophagus, blocking reflux mechanically rather than chemically.
Alginates are especially useful for reflux that happens after meals or when lying down, since the floating raft is most effective when there’s a pool of stomach contents to sit on top of. They can be combined with antacids or H2 blockers without concern, and they don’t carry the nutrient absorption risks of PPIs.
Choosing the Right Option
Your pattern of symptoms is the best guide:
- Occasional heartburn after eating: Antacids or an alginate product. Fast onset, no planning required.
- Predictable triggers like specific meals or bedtime: An H2 blocker taken 30 minutes beforehand. Longer prevention window than antacids.
- Frequent reflux, two or more days per week: A 14-day PPI course. The strongest option, but not instant.
- Immediate relief while starting a PPI: Combine antacids with your PPI for the first two to three days until the PPI reaches full effect.
Interactions and Age Limits
Calcium and magnesium-based antacids can interfere with the absorption of several common medications, including certain antibiotics (tetracyclines and quinolones), some antifungal medications, and NSAIDs like ibuprofen. If you take any prescription medications regularly, separate them from antacid doses by at least two hours.
For children, dedicated kids’ antacid tablets containing calcium carbonate are approved for ages 2 to 11, with dosing based on weight. Children under 2 should not be given OTC antacids without a doctor’s guidance. H2 blockers and PPIs have pediatric dosing, but these are generally prescription decisions for children rather than something to self-treat with adult OTC products.
Signs That OTC Treatment Isn’t Enough
OTC acid reflux medicines are meant for self-limited symptoms. Certain warning signs suggest something more serious is going on: difficulty swallowing or pain when swallowing, unexplained weight loss, persistent vomiting, loss of appetite, chest pain, or any sign of digestive bleeding such as vomit that looks like coffee grounds or stool that appears black and tarry. If your symptoms persist beyond two weeks of OTC treatment, that also signals the need for medical evaluation rather than another round of self-treatment.