Zantac today contains famotidine, a completely different active ingredient than the original version. The product was reformulated in 2020 after the FDA requested that all ranitidine products be pulled from the market due to a cancer-linked contaminant. If you’re picking up a box of Zantac 360 now, here’s exactly what’s inside and how it compares to what Zantac used to be.
The Active Ingredient in Today’s Zantac
Zantac 360 contains famotidine, the same active ingredient found in Pepcid AC. It comes in 10 mg and 20 mg over-the-counter tablets. Famotidine is an H2 blocker, meaning it works by attaching to specific receptors on the acid-producing cells in your stomach lining. Normally, after you eat, your body releases a chemical called histamine that binds to these receptors and triggers acid production. Famotidine gets there first and blocks histamine from attaching, so your stomach produces less acid.
This is the same mechanism the original Zantac used. Ranitidine was also an H2 blocker. The difference isn’t in how the drug works but in the chemical structure of the molecule itself, which matters because ranitidine’s structure turned out to be unstable in a dangerous way.
What the Original Zantac Contained
The original Zantac’s active ingredient was ranitidine hydrochloride. It came in several forms: 150 mg tablets (containing 168 mg of ranitidine hydrochloride), 300 mg tablets (336 mg of ranitidine hydrochloride), 25 mg effervescent tablets, and a liquid syrup with 15 mg of ranitidine per milliliter. For decades, it was one of the most widely used heartburn medications in the world.
Ranitidine is no longer sold in any form in the United States. You cannot get it by prescription or over the counter.
Why Ranitidine Was Pulled
In 2020, the FDA requested the withdrawal of all ranitidine products after testing revealed they contained NDMA, a probable human carcinogen. NDMA wasn’t added intentionally. It formed from the ranitidine molecule itself, particularly when exposed to heat over time.
The FDA set an acceptable daily intake limit for NDMA at 0.096 micrograms (0.32 parts per million). Testing of ranitidine products found NDMA in every single sample, and many exceeded this limit significantly. Brand-name Zantac 150 mg tablets showed NDMA levels ranging from 0.07 to 2.38 parts per million. Some generic versions were even higher: one 300 mg generic tested at 2.85 ppm, nearly nine times the acceptable limit.
The underlying problem turned out to be ranitidine’s chemical structure. Research found that the molecule degrades into NDMA when stored at elevated temperatures. The rate of degradation depended partly on the manufacturing process. Ranitidine crystals with certain structural defects broke down up to 100 times faster than those without, meaning some manufacturers’ products were far more contaminated than others. But because the instability was inherent to the molecule, no manufacturing fix could guarantee safety, and the FDA pulled the entire class.
Inactive Ingredients in Zantac 360
Beyond famotidine, the tablets contain several inactive ingredients that serve as binders, coatings, and fillers. The 10 mg and 20 mg tablets share most of the same list:
- Corn starch and microcrystalline cellulose: bulking agents that give the tablet its shape
- Hydroxypropyl cellulose and sodium starch glycolate: help the tablet break apart and dissolve in your stomach
- Hypromellose and carnauba wax: form the film coating on the outside
- Magnesium stearate: a lubricant used during manufacturing
- Titanium dioxide and red iron oxide: coloring agents
- Talc: prevents ingredients from sticking together
The 20 mg tablets also contain yellow iron oxide, which accounts for their slightly different color. Notably, the formulation does not contain lactose or gluten-based ingredients.
How Zantac 360 Compares to Pepcid
Zantac 360 and Pepcid AC contain the exact same active ingredient at the same dosages. Both are famotidine-based H2 blockers available in 10 mg and 20 mg strengths. The inactive ingredients differ slightly between the two brands, but functionally they work the same way. Choosing between them is essentially a matter of price, availability, or preference.
Who Should Avoid It
You should not take Zantac 360 if you’re allergic to famotidine or any other acid reducer. The label also warns against combining it with other acid-reducing medications. If you have kidney disease, talk to a pharmacist or doctor before taking it, since famotidine is processed through the kidneys. The same applies if you’re on any prescription medication, because acid reducers can change how certain drugs are absorbed.
Symptoms that look like heartburn can sometimes signal something more serious. Difficulty swallowing, vomiting blood, black or bloody stools, unexplained weight loss, or chest pain with shortness of breath and sweating are all signs that need medical evaluation rather than an over-the-counter acid reducer.