Over-the-counter medication · Proton Pump Inhibitor (PPI)
omeprazole
Also sold as Prilosec. This medicine treats frequent heartburn, which is heartburn that occurs 2 or more days a week.
Data updated 2026-05-15
- 331,875
- FDA reportsHeavily reported
- 27
- InteractionsSeveral interactions
- In shortage
- FDA status
What the data shows
omeprazole (Prilosec) is an over-the-counter Proton Pump Inhibitor (PPI), in the top 5% of tracked drugs by FAERS report volume (331,875 FDA reports), with 27 documented drug interactions.
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
omeprazole (Prilosec) is an over-the-counter Proton Pump Inhibitor (PPI). This medicine treats frequent heartburn, which is heartburn that occurs 2 or more days a week.
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).
Verify with FDA → · CMS NADAC pricing →
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.
The sections below are summarized in plain English from omeprazole's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
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.
This is a plain-language summary of omeprazole's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.
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.
This is a plain-language summary of omeprazole's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.
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.
This is a plain-language summary of omeprazole's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.
Storage
Store at room temperature away from moisture and heat.
Side Effects (from patient reports)
Based on 331,875 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for omeprazole, by number of reports
- Tiredness
Tiredness
19,903 reports
- Feeling sick to your stomach
Feeling sick to your stomach
19,841 reports
- Loose stools
Loose stools
19,625 reports
- Difficulty breathing
Difficulty breathing
16,336 reports
- Headache
Headache
14,629 reports
- Pain
Pain
13,761 reports
- Long-term kidney problem
Long-term kidney problem
13,547 reports
- Throwing up
Throwing up
13,263 reports
- Feeling lightheaded
Feeling lightheaded
13,106 reports
- Sudden kidney damage
Sudden kidney damage
11,753 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for omeprazole each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where omeprazole sits
omeprazole has more FDA adverse-event reports than 98% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is omeprazole; the line is the median (50th percentile).
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
Reports Mentioning Death
30,378
9.2% of reports — not proof of cause
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 |
| 6 | HEADACHE | 14,629 |
| 7 | PAIN | 13,759 |
| 8 | CHRONIC KIDNEY DISEASE | 13,547 |
| 9 | VOMITING | 13,263 |
| 10 | DIZZINESS | 13,108 |
| 12 | ACUTE KIDNEY INJURY | 11,753 |
| 13 | MALAISE | 10,918 |
| 14 | ASTHENIA | 10,698 |
| 15 | ARTHRALGIA | 10,694 |
| 16 | FALL | 10,630 |
| 17 | PNEUMONIA | 9,856 |
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,...
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...
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.
This is a plain-language summary of interactions documented in FDA labeling, not individualized advice. Ask a pharmacist or prescriber before combining medications.
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 →
Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
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Narrow Therapeutic Index Drugs
Why some drugs demand precise dosing and monitoring
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
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 331,875 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.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.
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