cimetidine vs nizatidine
Side-by-side comparison of cimetidine and nizatidine Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
Tagamet
Axid
Cimetidine (Tagamet) reduces stomach acid. It is used to treat ulcers, heartburn, and other conditions where too much acid is produced.
Nizatidine helps reduce stomach acid. It can treat ulcers and heartburn.
Cimetidine treats active duodenal ulcers for short periods. It can also be used long-term at a lower dose to prevent ulcers from returning. This medicine also treats active benign gastric ulcers for a short time. Additionally, it can help with erosive gastroesophageal reflux disease (GERD), which damages the esophagus.
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.
Cimetidine is an H2 receptor antagonist. This means it blocks histamine from attaching to certain cells in your stomach. By blocking histamine, cimetidine reduces the amount of acid your stomach makes.
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.
- • Headache
- • Dizziness
- • Diarrhea
- • Headache
- • Abdominal pain
- • Diarrhea
- • Nausea
- • Dizziness
- Long-term kidney disease 1,264
- Sudden kidney damage 710
- Kidney failure 694
- Feeling sick to your stomach 681
- Feeling tired 599
- Long-term kidney disease 264
- Sudden kidney damage 161
- Kidney failure 135
- Final stage of kidney disease 72
- Feeling sick to your stomach 67
Reversible confusional states (like mental confusion, agitation, or hallucinations) have been reported, mostly in severely ill patients. These usually appear within 2-3 days of starting treatment and clear up within 3-4 days of stopping the drug.
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.
Tell your doctor if you are pregnant or plan to become pregnant. The effects of cimetidine during pregnancy are not fully known. Talk to your doctor about the risks and benefits of taking cimetidine while breastfeeding.
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.
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How to Read This cimetidine vs nizatidine Comparison
cimetidine 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, cimetidine has 3,948 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 cimetidine 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.