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famotidine vs nizatidine

Side-by-side comparison of famotidine and nizatidine Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.

Drug Class
famotidine H2 Receptor Antagonist
nizatidine H2 Receptor Antagonist
Type
famotidine Over-the-Counter
nizatidine Over-the-Counter
Summary
famotidine

Famotidine (Pepcid) reduces stomach acid. It is used to treat ulcers, heartburn, and acid reflux.

nizatidine

Nizatidine helps reduce stomach acid. It can treat ulcers and heartburn.

What It Treats
famotidine

This medicine treats active duodenal ulcers and active gastric ulcers. It also treats heartburn (nonerosive GERD) and erosive esophagitis (damage to the esophagus from acid reflux). Famotidine can also treat conditions where the stomach makes too much acid, like Zollinger-Ellison syndrome. It can also lower the risk of duodenal ulcers coming back.

nizatidine

Nizatidine can treat active duodenal ulcers for up to 8 weeks. It can also be used long-term at a lower dose to prevent ulcers from returning. Nizatidine treats esophagitis (damage to the esophagus) and heartburn caused by GERD for up to 12 weeks. It can also treat active benign gastric ulcers for up to 8 weeks.

How It Works
famotidine

Famotidine is an H2 receptor antagonist. This means it blocks histamine, a substance that tells your stomach to make acid. By blocking histamine, famotidine reduces the amount of acid your stomach produces.

nizatidine

Nizatidine is an H2 receptor antagonist. This means it blocks histamine from attaching to cells in your stomach. By blocking histamine, the drug reduces the amount of acid your stomach makes.

Common Side Effects
famotidine
  • Headache
  • Dizziness
  • Constipation
  • Diarrhea
nizatidine
  • Headache
  • Abdominal pain
  • Diarrhea
  • Nausea
  • Dizziness
FAERS Reports
famotidine
  • Feeling sick to your stomach 7,259
  • Feeling tired 6,866
  • Long-term kidney problems 6,644
  • Loose, watery stools 6,448
  • The medicine is not working 6,151
nizatidine
  • Long-term kidney disease 264
  • Sudden kidney damage 161
  • Kidney failure 135
  • Final stage of kidney disease 72
  • Feeling sick to your stomach 67
Serious Warnings
famotidine

In elderly patients and those with kidney problems, famotidine can cause confusion, delirium, or hallucinations. If you are elderly or have kidney problems, your doctor may prescribe a lower dose. Famotidine can hide the symptoms of stomach cancer. If your symptoms don't improve, tell your doctor.

nizatidine

If you have kidney problems, your doctor may need to lower your dose. Before taking this medicine for a stomach ulcer, make sure it is not cancerous.

Pregnancy
famotidine

It is not known if famotidine will harm an unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. Famotidine may pass into breast milk, but it's not expected to harm the baby. Talk to your doctor about breastfeeding while taking this medicine.

nizatidine

Tell your doctor if you are pregnant or plan to become pregnant. It is not known if nizatidine will harm your unborn baby. Talk to your doctor if you are breastfeeding.

Also Compare — Nearby Drugs

How to Read This famotidine vs nizatidine Comparison

famotidine is classified in the H2 Receptor Antagonist drug class, while nizatidine sits within the H2 Receptor Antagonist class. Because both drugs share the same classification, they are often considered interchangeable in theory — but clinical outcomes rarely track that cleanly. Both drugs are available over the counter.

Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, famotidine has 33,368 submissions while nizatidine has 699. Those figures reflect cumulative reporting volume — not per-patient risk — so older, widely dispensed drugs typically look worse on count alone. No direct interaction between these two drugs is listed in our FDA-derived dataset, though co-prescription still warrants pharmacist review. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.

A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between famotidine and nizatidine — always consult your physician or pharmacist first.

Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.