Omeprazole (By mouth)


Omeprazole (oh-MEP-ra-zole)

Treats heartburn, stomach ulcers, gastroesophageal reflux disease (GERD), and conditions that cause your stomach to make too much acid, such as Zollinger-Ellison syndrome, endocrine tumors, and systemic mastocytosis. Also helps heal a damaged esophagus, and helps prevent stomach bleeding in patients who have a serious illness. This medicine may be used in combination with antibiotics to treat ulcers. This medicine is a proton pump inhibitor (PPI).

Brand Name(s)

Prilosec, Omeclamox-Pak, Quality Choice Omeprazole Magnesium, First - Omeprazole, Sunmark Omeprazole, Rite Aid Omeprazole, Good Sense Omeprazole, Prilosec OTC, The Medicine Shoppe Omeprazole, Leader Omeprazole, TopCare Omeprazole

There may be other brand names for this medicine.

When This Medicine Should Not Be Used

Do not use this medicine if you have had an allergic reaction to omeprazole or similar medicines, such as esomeprazole, lansoprazole, pantoprazole, Aciphex®, Nexium®, or Protonix®.

How to Use This Medicine

Delayed Release Capsule, Packet, Powder for Suspension, Delayed Release Tablet

  • Your doctor will tell you how much of this medicine to use and how often. Do not use more medicine or use it more often than your doctor tells you to.
  • This medicine comes with patient instructions. Read and follow these instructions carefully. Ask your doctor or pharmacist if you have any questions.
  • Take this medicine at least 1 hour before a meal and for the full time of treatment, even if you begin to feel better after a few days.
  • Delayed-release capsule or delayed-release tablet: Swallow the capsule or tablet whole. Do not crush, break, or chew it. You may open the capsule and pour the medicine into a small amount of soft food, such as applesauce if you cannot swallow it whole. Stir this mixture well and swallow it without chewing. Drink a full glass (8 ounces) of cool water to make sure you swallow all of the medicine.
  • Delayed-release oral suspension:
    • Empty the contents of a 2.5-milligram (mg) packet of powder into a container containing 5 mL of water.
    • OR
    • Empty the contents of a 10-mg packet of powder into a container containing 15 mL of water.
    • Use only water. Do not use other liquids or foods.
    • Stir well. Let the mixture thicken for 2 to 3 minutes.
    • Stir and drink within 30 minutes.
    • If any medicine remains after drinking, add more water, stir, and drink immediately.
  • Delayed-release oral suspension through a feeding tube:
    • Add 5 mL to a catheter-tipped syringe, and then add the contents of a 2.5-mg packet (or 15 mL of water for the 10-mg packet).
    • Shake the syringe right away. Let the mixture thicken for 2 to 3 minutes.
    • Shake the syringe once more and give the medicine through the nasogastric or gastric tube into the stomach within 30 minutes.
    • Refill the syringe with an equal amount of water.
    • Shake and flush any remaining contents through the nasogastric or gastric tube.
  • If you are using this medicine without a prescription, follow the instructions on the medicine label.
  • If you are using this medicine to treat heartburn, do not take it for more than 14 days unless your doctor tells you to. Also, do not use this 14-day treatment more often than every 4 months unless directed by your doctor.

If a dose is missed:

  • If you miss a dose or forget to use your medicine, use it as soon as you can. If it is almost time for your next dose, wait until then to use the medicine and skip the missed dose. Do not use extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine away from children and never share your medicine with anyone.

Drugs and Foods to Avoid

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Tell your doctor if you are also using ampicillin (Unasyn®), atazanavir (Reyataz®), clarithromycin (Biaxin®), clopidogrel (Plavix®), cyclosporine (Gengraf®, Neoral®, Sandimmune®), ketoconazole (Nizoral®), nelfinavir (Viracept®), saquinavir (Fortovase®, Invirase®), tacrolimus (Prograf®), or voriconazole (Vfend®). Tell your doctor if you are also using cilostazol (Pletal®), diazepam (Valium®), digoxin (Lanoxin®), disulfiram (Antabuse®), phenytoin (Dilantin®), rifampin (Rifadin®, Rimactane®), St John's wort, iron supplements, or a blood thinner (such as warfarin or Coumadin®).
  • Make sure your doctor knows if you are also using a diuretic (water pill, such as bumetanide, chlorothiazide, ethacrynic acid, furosemide, hydrochlorothiazide (HCTZ), indapamide, metolazone, torsemide, Bumex®, Demadex®, Diuril®, Edecrin®, Lasix®, Lozol®, or Zaroxolyn®), or certain medicines to treat high blood pressure (such as atenolol, enalapril, lisinopril, losartan, metoprolol, olmesartan, valsartan, Accupril®, Cozaar®, Diovan®, Lotrel®, Toprol®, or Zestril®).

Warnings While Using This Medicine

  • Make sure your doctor knows if you are pregnant or breastfeeding, or if you have liver disease, heart disease, osteoporosis, seizures, or a history of low magnesium levels in your blood. Ask a doctor if you should use this medicine if you also have nausea, vomiting, stomach pain, unexplained weight loss, or trouble breathing.
  • Before you use this medicine, tell your doctor if you have had heartburn longer than 3 months. Tell your doctor if you have trouble swallowing food, are vomiting blood, or have blood in your stools. These may be signs of a more serious stomach condition.
  • People of Asian race may react differently to this medicine.
  • This medicine may cause hypomagnesemia (low magnesium in the blood). This is more likely to occur if you take this medicine longer than 1 year, or if you take it with digoxin or certain diuretics (water pills). Stop using this medicine and tell your doctor right away if you have seizures, dizziness, a fast or pounding heartbeat, or muscle spasms.
  • You may be at risk for Clostridium difficile colitis (also called C diff) if you take this medicine. C diff is an inflammation of your large intestine that causes diarrhea. You have a higher risk of this condition if you are also using antibiotics, are elderly, or have other health conditions.If you have severe diarrhea, ask your doctor before taking any medicine to stop the diarrhea.
  • This medicine may increase your risk of broken bones in the hip, wrist, or spine. This is more likely if you are older than 50, if you receive high doses of this medicine, or if you use it for longer than 1 year.
  • If your symptoms do not improve or if they get worse, call your doctor.
  • This medicine is sometimes given together with other medicines to treat ulcers. Make sure you understand how to use the combination of medicines.
  • Your doctor will need to check your progress at regular visits while you are using this medicine. Be sure to keep all appointments.You may need blood or other lab tests to check for unwanted effects.

Possible Side Effects While Using This Medicine

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Blistering, peeling, or red skin rash
  • Fast, slow, or uneven heartbeat
  • Lightheadedness, dizziness, or fainting
  • Seizures, muscle spasms, or tremors
  • Severe diarrhea that does not go away, stomach pain, and fever
  • Sudden and severe stomach pain, nausea, or vomiting

If you notice these less serious side effects, talk with your doctor:

  • Constipation, diarrhea, gas, or stomach pain
  • Fever
  • Headache
  • Stuffy or runny nose, sneezing

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Version Info

  • Last Reviewed on 06/12/2013

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This page was last updated: September 18, 2013

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