How It Works
As a proton pump inhibitor (PPI), omeprazole works by decreasing the amount of acid your stomach produces.
| Quick Facts | |
|---|---|
| Common Brands | Prilosec, Prilosec OTC |
| Drug Class | Proton pump inhibitor (PPI) |
| Generic Status | Generic is available |
| Availability | Prescription only |
Dosing
Over-the-counter (OTC) omeprazole comes in 20 mg dosage strengths, while prescription omeprazole comes in 10 mg, 20 mg, and 40 mg strengths. The recommended dosage of omeprazole depends on what you are treating:
- Heartburn: The recommended dose is 20 mg by mouth once a day for 2 weeks.
- Gastroesophageal reflux disease (GERD): The recommended dose is 20 mg by mouth once a day for up to 4 weeks.
- Stomach or duodenal ulcer: The recommended dose is 20 mg or 40 mg by mouth once a day for 4 to 8 weeks.
- Reducing risk of duodenal ulcer due to H. pylori infection: The recommended dose is 20 mg of omeprazole, 1000 mg of amoxicillin, and 500 mg of clarithromycin — two times a day for 10 days (triple therapy); or 40 mg of omeprazole once a day and 500 mg of clarithromycin three times a day for 14 days (dual therapy).
- Erosive esophagitis: The recommended dose is 20 mg by mouth once a day for 4 to 8 weeks.
- Other conditions that cause excessive stomach acid: The recommended dose is 60 mg by mouth once a day. The maximum dose is 120 mg three times a day.
In general, omeprazole should be taken before a meal, typically 30 to 60 minutes before breakfast.
Note: Dosing information below is educational only. Your prescribing physician will determine your specific dose based on your individual health needs. Always follow your healthcare provider’s instructions for exact dosing.
Uses
FDA-Approved Uses
Omeprazole is FDA-approved to treat several conditions caused by excess stomach acid, including:
- Gastroesophageal reflux disease (GERD)
- Stomach or duodenal ulcers
- Erosive esophagitis (EE)
- H. pylori infection (usually in combination with other medications)
- Other conditions that cause too much stomach acid, e.g. Zollinger-Ellison syndrome
- Heartburn (OTC omeprazole only)
Off-Label Uses
You may see omeprazole prescribed for uses that are not “FDA-approved.” This is a common and legal practice called “off-label” prescribing, where a doctor uses their clinical judgment to prescribe a drug for a different (but well-researched) purpose.
Currently, there are no common off-label uses for omeprazole.
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Side Effects
Like all medications, omeprazole can cause side effects. Some common side effects may improve over time as your body adjusts to the medication. Other side effects may be serious and require medical attention.
Common Side Effects
- Headache
- Upset stomach
- Stomach pain
- Diarrhea
- Gas
- Nausea
- Vomiting
Serious Side Effects
Serious side effects are rare, but it’s important to know what to look for if they do occur. Stop using omeprazole and call your doctor immediately if you experience:
- Severe allergic reactions: Symptoms include swelling of the face, lips, tongue, or throat; difficulty breathing or swallowing; racing heart; severe rash or itching; and/or fever.
- Drug reaction with eosinophilia and system symptoms (DRESS): Omeprazole may also cause this specific type of allergic reaction that affects multiple organs. Symptoms include skin rash or hives, fever, dark urine, swollen lymph nodes, shortness of breath, yellowing of the skin or eyes, and swelling in the feet, ankles, or legs.
- Kidney problems: Acute tubulointerstitial nephritis can occur at any time while taking omeprazole. Symptoms include a decreased amount of urine or blood in the urine.
- Antibiotic-associated diarrhea (C. diff): PPIs like omeprazole may increase the risk of Clostridioides difficile infection, causing persistent or watery diarrhea, severe cramps, bloody stool, and fever.
- Bone loss or fractures: Long-term use of omeprazole or taking high doses may increase the risk of osteoporosis-related fractures of the hip, wrist, or spine. Older adults may also have an increased risk.
- Vitamin B12 (cyanocobalamin) deficiency: Taking omeprazole for 3 years or longer may affect your body’s ability to absorb vitamin B12. Symptoms include weakness, sore tongue, or numbness or tingling in the hands or feet.
- Low magnesium levels (hypomagnesemia): Omeprazole may lower magnesium levels, which can cause seizures or problems with your heart rhythm. The risk may be higher when taking omeprazole long term or with other medications that lower magnesium levels. Symptoms include muscle spasms, dizziness, seizures, or irregular heartbeat.
- Lupus: Omeprazole can cause or worsen some types of lupus, an autoimmune disorder. Symptoms include joint pain or a rash on the cheeks or arms.
- Severe skin reactions: Serious conditions like Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) may occur when taking omeprazole. Symptoms include painful or watery eyes, rash or blisters, and painful skin that peels or burns.
Call your doctor immediately if you experience any concerning or prolonged symptoms.
Pharmacist Tips
Swallow Pills Whole
Do not chew, cut, or crush omeprazole tablets or capsules. If you cannot swallow capsules, you may open them and sprinkle the pellets onto one tablespoon of applesauce. Swallow immediately without chewing the pellets, followed by a glass of cool water.
Prepare the Granules With Water
If you’re prescribed the oral granules, prepare the mixture with the recommended amount of water: 5 mL for the 2.5 mg packet and 15 mL for the 10 mg packet. Mix and stir, wait 2–3 minutes, and then stir again and drink the entire mixture within 30 minutes.
Take Your Dose Before Eating
It’s recommended to take omeprazole on an empty stomach, ideally 30 to 60 minutes before a meal (usually breakfast).
Store at Room Temperature
Omeprazole should be stored in a cool, dry place between 68°F to 77°F (20°C to 25°C).
Tell Your Doctor if You Are Pregnant or Breastfeeding
It is unknown if omeprazole harms an unborn baby, so risks cannot be ruled out. The medication passes into breast milk and should not be taken while breastfeeding.
Do Not “Double Up” for Missed Doses
If you miss a dose of omeprazole, take it as soon as you remember, unless it is time for your next dose. In that case, skip the missed dose and take your next dose as usual.
Drug Interactions
Certain medications and substances can interact with omeprazole, potentially altering how it works or increasing the risk of side effects. For example:
- Clopidogrel (Plavix): Omeprazole can significantly reduce the effectiveness of this blood thinner, increasing the risk of blood clots.
- Digoxin (Lanoxin): Omeprazole may interact with this heart medicine.
- Methotrexate (Trexall): Omeprazole can increase the risk of methotrexate toxicity.
- St. John’s wort: This supplement can lower the amount of omeprazole in your body and should not be taken at the same time.
- HIV/AIDS medications: Certain antiretrovirals like rilpivirine, nelfinavir, and atazanavir should not be taken with omeprazole.
- Warfarin (Coumadin): Taking omeprazole with this blood thinner may increase the risk of bleeding.
- Rifampin: Omeprazole should not be used with this tuberculosis medication.
Always give your doctor and pharmacist a complete list of all your medications, vitamins, and supplements to check for potential interactions.
FAQs
Why must I take omeprazole before eating breakfast?
It is recommended to take omeprazole 30 to 60 minutes before breakfast on an empty stomach. This timing is recommended because the medication works by blocking the acid pumps in your stomach, which are most active when you eat. Taking it beforehand helps ensure the medication is absorbed and ready to work when you need it.
Can I open the capsule if I can’t swallow pills?
Yes, if you have difficulty swallowing, you can open the capsules. Sprinkle the contents onto one tablespoon of applesauce and swallow it right away without chewing the pellets. If needed, you can have a glass of water afterward.
Why does the box say to only take Omeprazole for 14 days?
For OTC use, the limit is 14 days to prevent the medication from masking more serious underlying conditions. For example, frequent heartburn can be a warning sign for stomach cancer.
If you need heartburn medication for longer than 14 days, or more frequently than every 4 months, contact your health provider to rule out other medical issues.
Can I take omeprazole at night instead of in the morning?
While the standard recommendation is to take it in the morning before breakfast, your doctor may suggest a different schedule based on your situation. If prescribed twice daily, the first dose is typically before breakfast and the second before dinner.
Does Omeprazole block the absorption of vitamin B12?
Yes, using acid-lowering medications like omeprazole for a long period (typically 3 years or longer) can reduce the stomach acid your body needs to absorb vitamin B12. Over time, this can lead to low vitamin B12 levels.
Why did my heartburn get worse when I tried to stop taking it?
If your heartburn returns or worsens after stopping omeprazole, it may indicate that the underlying condition causing the acid reflux has not been fully resolved. Contact your healthcare provider to discuss any symptoms that get worse or don’t go away.
Is omeprazole safe to take with Plavix (clopidogrel)?
No, it is not recommended. Omeprazole can cause clopidogrel (Plavix) to not work as well, which increases the risk of blood clots.
Can I take Tums or Mylanta at the same time as omeprazole?
Yes, your provider might recommend taking an antacid like calcium carbonate (Tums) with omeprazole. Omeprazole can take 1 to 4 days to fully take effect, and antacids can provide immediate relief for heartburn symptoms in the interim.
Is omeprazole safe to use during pregnancy?
Existing studies suggest omeprazole is not likely to cause serious birth defects, but risk cannot be ruled out. Consult your healthcare provider before taking it if you are pregnant or planning to become pregnant.
Can I drink alcohol while taking omeprazole?
It is unknown if drinking alcohol interacts directly with omeprazole. However, alcohol can trigger heartburn symptoms.
What is the difference between omeprazole tablets and capsules?
Both forms contain the same active ingredient. The difference lies in how you take them. Capsules are typically swallowed whole or opened onto applesauce, while tablets are designed to be swallowed whole or dissolved in the mouth (orally disintegrating tablets).
Can I take ibuprofen or aspirin with omeprazole?
While omeprazole does not list ibuprofen or aspirin in its common drug interactions, omeprazole is sometimes used to prevent ulcers that can be caused by NSAIDs like aspirin or ibuprofen. It’s recommended to tell your healthcare provider about all medicines or supplements you are using before starting omeprazole.
How long does it take for omeprazole to start working fully?
Omeprazole is not used for immediate heartburn relief. It usually takes 1 to 4 days for omeprazole to start working fully, although some people may experience improvement within the first 24 hours.
Can I take probiotics with omeprazole?
There are no specific warnings against probiotics in the prescribing information for omeprazole. However, it can interact with other supplements such as St. John’s wort. It’s always recommended to inform your healthcare provider about any supplements you are taking to check for interactions.
Comparable Medications
Omeprazole, esomeprazole (Nexium), pantoprazole (Protonix), or lansoprazole (Prevacid)?
There are several medications that your doctor can prescribe in place of omeprazole. Here are a few possible alternatives below.
Esomeprazole
From $34.99
A proton pump inhibitor used to treat conditions caused by excessive stomach acid such as GERD, stomach ulcers, or erosive esophagitis (prescription only) or to relieve heartburn (over-the-counter).
Pantoprazole Tablets
From $19.99
A proton pump inhibitor used to treat conditions caused by excessive stomach acid such as GERD, stomach ulcers, or erosive esophagitis
Lansoprazole Capsules
From $29.99
A proton pump inhibitor used to treat conditions caused by excessive stomach acid such as GERD, stomach ulcers, or erosive esophagitis.
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Important: Information on this page is for educational purposes only. Prescribing decisions are made by independent, licensed providers. TelyRx operates technology-enabled pharmacies and a telehealth platform that connects patients with board-certified licensed providers. Prescriptions, when provider-approved and issued, are filled and shipped by TelyRx-affiliated pharmacies. We do not employ physicians or make prescribing decisions. Learn more about our editorial standards here.