omeprazole
Brand names: Prilosec
Omeprazole (Prilosec) is a medicine that reduces the amount of acid in your stomach. It belongs to a class of drugs called proton pump inhibitors (PPIs).
Drug Shortage Alert
omeprazole is currently listed as to be discontinued by the FDA. Affected manufacturer: Sandoz Inc..
View all drug shortages →Drug Pricing (NADAC)
Generic Price
$0.07/unit
Generic Available
Yes (30 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
This medicine treats frequent heartburn, which is heartburn that occurs 2 or more days a week.
Common side effects
Headache
Key warnings
Children under 18 should ask a doctor before use.
How It Works
Omeprazole works by blocking the production of acid in your stomach. It does this by targeting the cells that make stomach acid. This helps to reduce heartburn symptoms.
How to Take It
Adults 18 and older should take 1 tablet daily (every 24 hours) for 14 days. Swallow 1 tablet with a glass of water before you eat in the morning. Take it every day for 14 days. Do not take more than 1 tablet a day. Swallow the tablet whole; do not chew or crush it.
Pregnancy & Breastfeeding
Talk to your doctor if you are pregnant or breastfeeding before taking this medicine. It is important to weigh the benefits and risks with your doctor.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule.
Storage
Store at room temperature away from moisture and heat.
Side Effects (from patient reports)
Based on 159,653 FDA adverse event reports.
FDA Adverse Event Report Analysis
Detailed analysis of 331,875 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 1999–2025.
Total Reports
331,875
Death-Related Reports
30,378
Hospitalization Reports
122,601
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | FATIGUE | 19,901 |
| 2 | NAUSEA | 19,842 |
| 3 | DIARRHOEA | 19,627 |
| 4 | DYSPNOEA | 16,336 |
| 5 | DRUG INEFFECTIVE | 15,639 |
| 6 | HEADACHE | 14,629 |
| 7 | PAIN | 13,759 |
| 8 | CHRONIC KIDNEY DISEASE | 13,547 |
| 9 | VOMITING | 13,263 |
| 10 | DIZZINESS | 13,108 |
| 11 | OFF LABEL USE | 12,603 |
| 12 | ACUTE KIDNEY INJURY | 11,753 |
| 13 | MALAISE | 10,918 |
| 14 | ASTHENIA | 10,698 |
| 15 | ARTHRALGIA | 10,694 |
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
Children under 18 should ask a doctor before use. Heartburn in children may be a sign of a serious condition.
Known Drug Interactions
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: Omeprazole does not change how fast your body breaks down and gets rid of theophylline.
What to do: You can usually take these two medicines together without changing your dose.
Proton Pump Inhibitors: Omeprazole No Dose Adjustment Omeprazole: The mean 24-hour gastric pH value was 5.2 when omeprazole was administered alone and 5.7 when coadministered with clarithromycin as a result of increased omeprazole exposures [see Pharmacokinetics ( 12.3 )] (see also Omeprazole under “Drugs That Affect Clarithromycin Tablets” in the table below). Saquinavir (in patients with normal renal function) Ritonavir (in patients with normal renal function) No Dose Adjustment Proton Pump Inhibitors: Omeprazole Use With Caution Omeprazole: Clarithromycin concentrations in the gastric ti...
Mechanism: Clarithromycin slows down how your body processes omeprazole, which leads to higher levels of the stomach medicine in your system.
What to do: Use this combination with caution and follow your doctor's instructions for monitoring your symptoms.
Omeprazole or Esomeprazole Avoid concomitant use of clopidogrel with omeprazole or esomeprazole. In clinical studies, omeprazole was shown to reduce significantly the antiplatelet activity of clopidogrel when given concomitantly or 12 hours apart. A similar reduction in antiplatelet activity was observed with esomeprazole when given concomitantly with clopidogrel.
Mechanism: Omeprazole stops clopidogrel from working correctly by preventing it from turning into its active form. This makes the medicine less effective at stopping blood clots.
What to do: Avoid taking these two drugs together. Your doctor may suggest a different medicine for your stomach.
Proton pump inhibitor: omeprazole ↓ omeprazole ↔ darunavir When omeprazole is co-administered with darunavir/ritonavir, monitor patients for decreased efficacy of omeprazole. Consider increasing the omeprazole dose in patients whose symptoms are not well controlled; avoid use of more than 40 mg per day of omeprazole.
Mechanism: Darunavir can lower the amount of omeprazole in your body, making the stomach medicine less effective at treating acid. This happens because of how the drugs interact during processing in the body.
What to do: Tell your doctor if your acid reflux symptoms get worse. They may increase your omeprazole dose, but you should not take more than 40 mg per day.
Mild or Moderate CYP3A Inhibitors: Clotrimazole, antibiotics (e.g., verapamil, diltiazem, nifedipine, nicardipine), amiodarone, danazol, ethinyl estradiol, cimetidine, lansoprazole and omeprazole May increase tacrolimus whole blood trough concentrations and increase the risk of serious adverse reactions (e.g., neurotoxicity, QT prolongation) [see Warnings and Precautions ( 5.7 , 5.10 , 5.11 )] .
Mechanism: Omeprazole slows down the process your body uses to remove tacrolimus, which can cause the drug to reach risky levels in your blood.
What to do: Your doctor should monitor your blood levels closely to watch for signs of serious side effects like nerve or heart issues.
Common Questions
How long does it take for omeprazole to work?
Can I take more than 1 tablet a day?
How often can I repeat a 14-day course of treatment?
Can children take this medicine?
Should I take this medicine with food?
What should I do if I still have heartburn after 14 days?
Can I chew or crush the tablet?
What if I miss a dose?
Can I take this medicine for immediate relief of heartburn?
What should I tell my doctor before taking this medicine?
What are the common side effects of omeprazole?
Does omeprazole interact with other medications?
What drug class is omeprazole?
Is omeprazole safe during pregnancy?
Has omeprazole been recalled?
Is omeprazole currently in shortage?
Active Recalls
Presence of foreign tablets/capsules: presence of foreign Divalproex Sodium Extended-Release 250mg tablet in a bottle of omeprazole capsules.
Dr. Reddy's Laboratories, Inc.
Related Medications in Proton Pump Inhibitor (PPI)
Other drugs grouped near omeprazole — 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 omeprazole →
aprepitant
Emend
Aprepitant (Emend) is a medicine that helps prevent nausea and vomiting.
Compare with omeprazole →
bisacodyl
Dulcolax
Bisacodyl is a medicine that helps you have a bowel movement.
Compare with omeprazole →
bismuth subsalicylate
Pepto-Bismol
Bismuth subsalicylate (Pepto-Bismol) is a medicine that can treat diarrhea and upset stomach.
Compare with omeprazole →
cimetidine
Tagamet
Cimetidine (Tagamet) reduces stomach acid.
Compare with omeprazole →
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Related Health & Safety Data
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What the FDA Data Shows for omeprazole
The FDA label for omeprazole (sold under brand names such as Prilosec) classifies it as an over-the-counter product in the Proton Pump Inhibitor (PPI) class. This medicine treats frequent heartburn, which is heartburn that occurs 2 or more days a week. 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 159,653 voluntary reports. The database also lists 27 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated major severity. NADAC pricing from CMS shows a generic unit cost of $0.07.
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 1 recall record 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). Pricing: CMS National Average Drug Acquisition Cost (NADAC). Shortage status: FDA Drug Shortages Database.
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: November 10, 2024
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