Cimetidine: uses, dosing, side effects & brands
Cimetidine is a histamine-2 receptor antagonist sold in the U.S. under 5 brand and generic names, for duodenal ulcer, dyspepsia and peptic esophagitis. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Drug class
- Histamine-2 Receptor Antagonist
- Treats (across its forms)
- Duodenal Ulcer, Dyspepsia and Peptic Esophagitis
- Available as
- Tablet · Suspension · Injectable · Solution
- Sold as
- 5 products — Tagamet, Tagamet Hb and Tagamet Hb 200, and others
- Prescription?
- Both Rx and OTC forms
- Generic available?
- Yes
- What the pharmacy pays
- about $10 for a 30-count supply — not your price
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How Cimetidine Hydrochloride is dosed
From the FDA label for Cimetidine Hydrochloride (application ANDA074251). Other cimetidine products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
Duodenal Ulcer Active Duodenal Ulcer: Clinical studies have indicated that suppression of nocturnal acid is the most important factor in duodenal ulcer healing (see Clinical Pharmacology-Antisecretory Activity-Acid Secretion ). This is supported by recent clinical trials (see Clinical Pharmacology-Clinical Trials Duodenal Ulcer-Active Duodenal Ulcer ). Therefore, there is no apparent rationale, except for familiarity with use, for treating with anything other than a once-daily at bedtime dosage regimen (h.s.). In a U.S. oral dose-ranging study of 400 mg h.s., 800 mg h.s. and 1600 mg h.s., a continuous dose response relationship for ulcer healing was demonstrated. However, 800 mg h.s. is the dose of choice for most patients, as it provides a high healing rate (the difference between 800 mg h.s. and 1600 mg h.s. being small), maximal pain relief, a decreased potential for drug interactions (see Precautions-Drug Interactions ) and maximal patient convenience. Patients unhealed at 4 weeks, or those with persistent symptoms, have been shown to benefit from two to four weeks of continued therapy. It has been shown that patients who both have an endoscopically demonstrated ulcer larger than 1 cm and are also heavy smokers (i.e., smoke one pack of cigarettes or more per day) are more difficult to heal. There is some evidence which suggests that more rapid healing can be achieved in…
Everything below is the FDA label for Cimetidine Hydrochloride (solution). Cimetidine is also sold as tablet, suspension and injectable, and those are different medicines to take — follow the label for the one you were prescribed.
Cimetidine Hydrochloride side effects
To report SUSPECTED ADVERSE REACTIONS, contact Chartwell RX, LLC. at 1-845-232-1683 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . Adverse effects reported in patients taking cimetidine are described below by body system. Incidence figures of 1 in 100 and greater are generally derived from controlled clinical studies. Gastrointestinal Diarrhea (usually mild) has been reported in approximately 1 in 100 patients. CNS Headaches ranging from mild to severe have been reported in 3.5% of 924 patients taking 1600 mg/day, 2.1% of 2,225 patients taking 800 mg/day and 2.3% of 1,897 patients taking placebo. Dizziness and somnolence (usually mild) have been reported in approximately 1 in 100 patients on either 1600 mg/day or 800 mg/day. Reversible confusional states, e.g., mental confusion, agitation, psychosis, depression, anxiety, hallucinations, disorientation, have been reported predominantly, but not exclusively, in severely ill patients. They have usually developed within 2 to 3 days of initiation of cimetidine therapy and have cleared within 3 to 4 days of discontinuation of the drug. Endocrine Gynecomastia has been reported in patients treated for one month or longer. In patients being treated for pathological hypersecretory states, this occurred in about 4% of cases while in all others the incidence was 0.3% to 1% in various studies. No evidence of induced endocrine…
Who shouldn’t take Cimetidine Hydrochloride
Cimetidine is contraindicated for patients known to have hypersensitivity to the product.
Every cimetidine product we track (5)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
| # | Drug | Rating | Type | Form | Generic? | Pharmacy pays | |
|---|---|---|---|---|---|---|---|
| 1 | 70/100 | Prescription | Tablet | Generic | $10 | View → | |
| 2 | 70/100 | Over-the-counter | Tablet | Generic | $10 | View → | |
| 3 | 70/100 | Prescription | Suspension | Generic | $10 | View → | |
| 4 | 70/100 | Prescription | Injectable | Generic | $10 | View → | |
| 5 | Not yet rated | Prescription | Solution | Generic | $10 | View → |
What cimetidine pills look like
Imprint codes, colour and shape from the FDA’s labelling data. Match the imprint on your pill — or search any imprint.
How long cimetidine keeps
No cimetidine label we read sets a separate limit for after opening, but they do specify how it must be stored — and the stability behind any date assumes those conditions.
Does cimetidine expire? The in-use limits and storage rules from its labelsCimetidine and breastfeeding
From LactMed, the US National Library of Medicine’s Drugs and Lactation Database — quoted, not rewritten.
Full LactMed record for cimetidine: levels in milk, effects in breastfed infants, and the drugs it would consider insteadMaternal cimetidine doses of 1000 to 1200 mg daily result in infant dosages that are much less than reported neonatal dosages of 5 to 10 mg/kg daily. Cimetidine would not be expected to cause any adverse effects in breastfed infants, especially if the infant is older than 2 months. However, because of its potential for causing hepatic enzyme inhibition, other drugs might be preferred. Cimetidine can increase serum prolactin and it has been used, but not validated, as a galactogogue.
National Institute of Child Health and Human Development, record revised September 15, 2024. LactMed states its information is not a substitute for professional judgement.
What people report to the FDA about cimetidine
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 6,586 reports naming cimetidine, and the FDA flagged 84% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- chronic kidney disease922 reports
- acute kidney injury525 reports
- nausea464 reports
- renal failure456 reports
- fatigue415 reports
- dyspnoea328 reports
- vomiting322 reports
- diarrhoea297 reports
Read these as a signal, not a rate. A report does not mean cimetidine caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved August 25, 2026.
Related calculators
Frequently asked questions
What is Cimetidine Hydrochloride?
Cimetidine Hydrochloride is a histamine-2 receptor antagonist used to treat Duodenal Ulcer, Dyspepsia, Peptic Esophagitis, Gastroesophageal Reflux.
What kind of drug is cimetidine?
The FDA classifies cimetidine as a histamine-2 receptor antagonist. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
Can you take cimetidine with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run cimetidine against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is cimetidine sold under?
We track 5 cimetidine-containing products in the U.S.: Tagamet, Tagamet Hb, Tagamet Hb 200, Tagamet Hydrochloride in Sodium Chloride 0.9% in Plastic Container and Cimetidine Hydrochloride. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does cimetidine come in?
Across the brands we track, cimetidine is currently marketed as tablet, suspension, injectable and solution, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic cimetidine?
Yes. Our catalog lists 1 generic cimetidine product alongside the brand versions. A generic has the same active ingredient and must meet the FDA's bioequivalence standard; it usually costs less. Ask your pharmacist which one your plan covers.
Cite this page
- APA
- pharmaranks. (2026, July 24). Cimetidine: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/cimetidine
- MLA
- “Cimetidine: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/cimetidine.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for cimetidine on DailyMed (NIH) ↗.