Zantac 360 is an over-the-counter heartburn medication containing famotidine, a completely different active ingredient from the original Zantac. It comes in 10 mg and 20 mg tablets, works within 15 to 20 minutes, and controls stomach acid for up to 12 hours per dose.
If the name sounds familiar but confusing, that’s because the Zantac brand underwent a major change. The product on shelves today is not the same drug that was sold under that name for decades.
Why the Original Zantac Was Pulled
The original Zantac contained ranitidine, a widely used acid reducer that had been available since the 1980s. In 2020, the FDA requested the removal of all ranitidine products from the market after discovering they contained a contaminant called NDMA, a substance linked to cancer at high levels. FDA testing found that NDMA levels in ranitidine increased over time, even under normal storage conditions. Higher temperatures and longer shelf life made the problem worse, potentially pushing NDMA above the acceptable daily intake limit.
The Zantac brand later relaunched as Zantac 360, this time built around famotidine. FDA testing has not found NDMA contamination in famotidine. Famotidine is the same active ingredient found in Pepcid AC, so while Zantac 360 carries the old brand name, it is chemically identical to Pepcid AC at matching doses.
How It Works
Famotidine belongs to a class of drugs called H2 blockers. After you eat, your stomach releases histamine, which signals acid-producing cells in your stomach lining to ramp up. Famotidine blocks the receptors where histamine normally docks on those cells, so the signal never gets through. The result is less stomach acid overall, both the baseline amount your stomach produces between meals and the surge that happens after eating.
This is different from antacids like Tums, which neutralize acid that’s already in your stomach. Famotidine prevents the acid from being produced in the first place, which is why its effects last much longer.
What It Treats
Zantac 360 is sold over the counter for three purposes: relieving heartburn that’s already started, relieving acid indigestion and sour stomach, and preventing heartburn before it begins. That prevention use is what makes it particularly practical. If you know that spicy food, coffee, or alcohol triggers your heartburn, you can take a tablet before the meal and avoid symptoms entirely.
How to Take It
The timing depends on which strength you’re using. For the 10 mg tablet, take one with a glass of water anywhere from 15 to 60 minutes before eating or drinking something that triggers heartburn. For the 20 mg tablet, the window is slightly wider: 10 to 60 minutes before the trigger food or drink. If heartburn has already started, you can take a tablet for relief without worrying about meal timing.
The maximum for either strength is two tablets in 24 hours. A single dose controls acid for up to 12 hours, so spacing two doses across a full day provides close to around-the-clock coverage when needed.
Side Effects
Most people tolerate famotidine well. Headache, dizziness, and constipation or diarrhea are the side effects that come up most often, and they’re typically mild. Serious reactions are rare but can include changes in heart rhythm, particularly a fast or irregular heartbeat. This risk is higher in older adults and people with kidney disease.
Kidney function matters because the body clears famotidine through the kidneys. If your kidneys work more slowly, the drug stays in your system longer and its effects intensify. Older adults are more likely to have some degree of reduced kidney function, even without knowing it, which is why age is flagged as a consideration.
Zantac 360 vs. Pepcid AC
They are the same drug. Both contain famotidine, both are available in matching strengths, and both work identically in the body. The choice between them comes down to price, availability, and brand preference. There is no clinical reason to choose one over the other. If your pharmacy is out of one, the other is a direct substitute.
How It Compares to PPIs
Proton pump inhibitors like omeprazole (Prilosec) and esomeprazole (Nexium) are a stronger class of acid reducers. They block acid production through a different mechanism and are generally more effective for frequent, persistent heartburn or conditions like GERD. But they take longer to reach full effect, often one to four days of daily use, and are designed for 14-day treatment courses rather than as-needed use.
Zantac 360’s advantage is speed and flexibility. It starts working in as little as 15 minutes, making it useful for occasional heartburn or predictable triggers. If you only get heartburn a few times a week, an H2 blocker like famotidine is often enough. If you’re dealing with heartburn most days, a PPI may be more appropriate.