ranitidine
Brand names: Zantac
Ranitidine (Zantac) helps reduce stomach acid. It can relieve heartburn and sour stomach.
What it does
This medicine treats heartburn caused by acid indigestion and sour stomach.
Common side effects
Headache
Key warnings
There are no boxed warnings in the provided data.
How It Works
Ranitidine is an H2 receptor antagonist. It works by blocking histamine. Blocking histamine reduces the amount of acid your stomach makes.
How to Take It
Adults and children 12 years and older can take this medicine. To relieve symptoms, swallow 1 tablet with a glass of water. To prevent symptoms, swallow 1 tablet with a glass of water 30 to 60 minutes before eating or drinking. You can take it up to twice a day, but do not take more than 2 tablets in 24 hours. Children under 12 years should ask a doctor.
Pregnancy & Breastfeeding
There is no information about pregnancy or breastfeeding in the provided data. Talk to your doctor if you are pregnant or breastfeeding.
Missed Dose
If you miss a dose, take it as soon as you remember. Do not take more than 2 tablets in 24 hours.
Storage
Store this medicine as directed by your doctor or pharmacist.
Side Effects (from patient reports)
Based on 139,052 FDA adverse event reports.
FDA Adverse Event Report Analysis
Detailed analysis of 197,405 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 1999–2025.
Total Reports
197,405
Death-Related Reports
15,440
Hospitalization Reports
25,953
Top Indication
Dyspepsia
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | BREAST CANCER | 24,853 |
| 2 | PROSTATE CANCER | 22,252 |
| 3 | COLORECTAL CANCER | 17,674 |
| 4 | BLADDER CANCER | 16,746 |
| 5 | RENAL CANCER | 16,278 |
| 6 | OESOPHAGEAL CARCINOMA | 9,648 |
| 7 | INCORRECT DOSE ADMINISTERED | 9,631 |
| 8 | HEPATIC CANCER | 7,592 |
| 9 | GASTRIC CANCER | 7,538 |
| 10 | PANCREATIC CARCINOMA | 6,840 |
| 11 | LUNG NEOPLASM MALIGNANT | 6,759 |
| 12 | NAUSEA | 4,715 |
| 13 | CHRONIC KIDNEY DISEASE | 4,687 |
| 14 | FATIGUE | 4,464 |
| 15 | DRUG INEFFECTIVE | 4,031 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
There are no boxed warnings in the provided data.
Known Drug Interactions
Dose adjustment is not recommended for risperidone tablets when co-administered with ranitidine, cimetidine, amitriptyline, or erythromycin [see Table 18 ] . Do not exceed twice the patient’s usual dose Enzyme (CYP3A) inhibitors Ranitidine 150 mg twice daily 1 mg single dose 1.2 1.4 Dose adjustment not needed Cimetidine 400 mg twice daily 1 mg single dose 1.1 1.3 Dose adjustment not needed Erythromycin 500 mg four times daily 1 mg single dose 1.1 0.94 Dose adjustment not needed Other Drugs Amitriptyline 50 mg twice daily 3 mg twice daily 1.2 1.1 Dose adjustment not Needed *Change relative t...
Mechanism: Ranitidine causes a small increase in risperidone levels, but it is not enough to change how the drug works or its safety.
What to do: No dose adjustment is necessary when these two medications are used together.
albuterol, systemic and inhaled mebendazole amoxicillin medroxyprogesterone ampicillin, with or without sulbactam methylprednisolone atenolol metronidazole azithromycin metoprolol caffeine, dietary ingestion nadolol cefaclor nifedipine co-trimoxazole (trimethoprim and sulfamethoxazole) nizatidine diltiazem norfloxacin dirithromycin ofloxacin enflurane omeprazole famotidine prednisone, prednisolone felodipine ranitidine finasteride rifabutin hydrocortisone roxithromycin isoflurane Sorbitol (purgative doses do not inhibit theophylline absorption) isoniazid sucralfate isradipine terbutaline, s...
Mechanism: Ranitidine can slow down how quickly your liver processes theophylline, which may cause the drug to build up to unsafe levels in your body.
What to do: Your doctor may need to check your blood levels more frequently and adjust your dose if necessary.
Cimetidine and Ranitidine Cimetidine and ranitidine do not affect the clearance of valproate.
Mechanism: Ranitidine does not change how the body processes or removes valproate from your system. There is no known interaction between these two drugs based on the provided information.
What to do: These medications can be taken together as prescribed. No dosage adjustments are usually necessary.
Other Drug Interactions Caution is advised when midazolam is administered concomitantly with drugs that are known to inhibit the P450-3A4 enzyme system such as cimetidine (not ranitidine), erythromycin, diltiazem, verapamil, ketoconazole and itraconazole. The effect of single oral doses of 800 mg cimetidine and 300 mg ranitidine on steady-state concentrations of midazolam was examined in a randomized crossover study (n=8). Ranitidine increased the mean steady-state concentration to 62 ng/mL.
Mechanism: Ranitidine can cause midazolam levels to build up in your body. This happens because the drug is processed more slowly than usual.
What to do: Use caution when taking these medicines together. Your doctor may need to watch you closely for extra sleepiness.
Effect of Other Drugs on the Pharmacokinetics of Clonazepam: Literature reports suggest that ranitidine, an agent that decreases stomach acidity, does not greatly alter clonazepam pharmacokinetics.
Mechanism: Ranitidine reduces stomach acid but does not have a major effect on how clonazepam moves through your body.
What to do: No specific action is typically required when taking these medications together.
Common Questions
What is ranitidine used for?
How often can I take ranitidine?
Can children take ranitidine?
How long before eating should I take ranitidine?
How many tablets can I take in a day?
What should I do if I miss a dose?
Can I take ranitidine while pregnant?
Can I take ranitidine while breastfeeding?
Does ranitidine have side effects?
How should I store ranitidine?
What are the common side effects of ranitidine?
Does ranitidine interact with other medications?
What drug class is ranitidine?
Is ranitidine safe during pregnancy?
Has ranitidine been recalled?
Active Recalls
CGMP Deviations: Presence of NDMA impurity detected in product.
Glenmark Pharmaceuticals Inc., USA
CGMP Deviations: Presence of NDMA impurity detected in product.
Glenmark Pharmaceuticals Inc., USA
CGMP Deviations: Presence of NDMA impurity detected in product.
Glenmark Pharmaceuticals Inc., USA
CGMP Deviations: Presence of NDMA impurity detected in product.
Glenmark Pharmaceuticals Inc., USA
CGMP Deviations: Impurity N-nitrosodimethylamine (NDMA) found in API
Granules India Limited
CGMP Deviations: Impurity N-nitrosodimethylamine (NDMA) found in API
Amneal Pharmaceuticals, Inc.
CGMP Deviations: N-nitrosodimethylamine (NDMA) has been detected in Ranitidine tablets, capsules and syrups.
AuroMedics Pharma LLC
CGMP Deviations: Presence of NDMA impurity detected in product.
Sanofi-Aventis U.S. LLC
CGMP Deviations: Presence of NDMA impurity detected in product.
Sanofi-Aventis U.S. LLC
CGMP Deviations: Presence of NDMA impurity detected in product.
Sanofi-Aventis U.S. LLC
CGMP Deviations: Presence of NDMA impurity detected in product.
Sanofi-Aventis U.S. LLC
CGMP Deviations: Presence of NDMA impurity detected in product.
Sanofi-Aventis U.S. LLC
Related Medications in H2 Receptor Antagonist
Other drugs grouped near ranitidine — same-class peers and common alternatives.
alosetron
Lotronex
Alosetron (Lotronex) is a medicine for women with severe diarrhea-predominant irritable bowel syndrome (IBS).
Compare with ranitidine →
aprepitant
Emend
Aprepitant (Emend) is a medicine that helps prevent nausea and vomiting.
Compare with ranitidine →
bisacodyl
Dulcolax
Bisacodyl is a medicine that helps you have a bowel movement.
Compare with ranitidine →
bismuth subsalicylate
Pepto-Bismol
Bismuth subsalicylate (Pepto-Bismol) is a medicine that can treat diarrhea and upset stomach.
Compare with ranitidine →
cimetidine
Tagamet
Cimetidine (Tagamet) reduces stomach acid.
Compare with ranitidine →
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What the FDA Data Shows for ranitidine
The FDA label for ranitidine (sold under brand names such as Zantac) classifies it as an over-the-counter product in the H2 Receptor Antagonist class. This medicine treats heartburn caused by acid indigestion and sour stomach. Official labeling lists 1 commonly reported side effect, including Headache.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 139,052 voluntary reports. The database also lists 15 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated major severity. Acquisition-cost data is surveyed weekly by CMS and updated as manufacturers report changes.
Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history (currently 12 recall records on file), and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: May 23, 2025
Read our methodology — how this data is sourced, computed, and verified.
All federal data sources used on this page
- FDA Orange Book — approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed — NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) — post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm — standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files — federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database — current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages