Generic name: omeprazole (oh MEP ra zol)
Brand name: FIRST Omeprazole, Omeprazole + SyrSpend SF Alka, PriLOSEC, PriLOSEC OTC, Zegerid (Original Formulation)
Dosage forms: oral delayed release capsule (10 mg; 20 mg; 40 mg); oral delayed release tablet (20 mg); oral powder for reconstitution, delayed release (10 mg; 2.5 mg); oral suspension (2 mg/mL)
Drug class: Proton pump inhibitors
Medically reviewed by Sanjai Sinha, MD. Last updated on July 21, 2021.
What is omeprazole?
Omeprazole is a proton pump inhibitor that decreases the amount of acid produced in the stomach.
Omeprazole is used to treat symptoms of gastroesophageal reflux disease (GERD) and other conditions caused by excess stomach acid. It is also used to promote healing of erosive esophagitis (damage to your esophagus caused by stomach acid).
Omeprazole may also be given together with antibiotics to treat gastric ulcer caused by infection with Helicobacter pylori (H. pylori).
Over-the-counter (OTC) omeprazole is used in adults to help control heartburn that occurs 2 or more days per week. The OTC brand must be taken as a course on a regular basis for 14 days in a row.
Omeprazole can cause kidney problems. Tell your doctor if you are urinating less than usual, or if you have blood in your urine.
Diarrhea may be a sign of a new infection. Call your doctor if you have diarrhea that is watery or has blood in it.
Omeprazole is not to used for the immediate relief of heartburn symptoms.
You may be more likely to have a broken bone while taking this medicine long term or more than once per day.
Before taking this medicine
Heartburn can mimic early symptoms of a heart attack. Get emergency medical help if you have chest pain that spreads to your jaw or shoulder and you feel sweaty or light-headed.
You should not use omeprazole if you are allergic to it, or if:
you had breathing problems, kidney problems, or a severe allergic reaction after taking omeprazole in the past; or
Ask a doctor or pharmacist if this medicine is safe to use if you have:
trouble or pain with swallowing;
bloody or black stools, vomit that looks like blood or coffee grounds;
heartburn that has lasted for over 3 months;
frequent chest pain, heartburn with wheezing;
low levels of magnesium in your blood; or
You may be more likely to have a broken bone in your hip, wrist, or spine while taking a proton pump inhibitor long-term or more than once per day. Talk with your doctor about ways to keep your bones healthy.
Ask a doctor before using this medicine if you are pregnant or breastfeeding.
Do not give this medicine to a child without medical advice.
How should I take omeprazole?
Take omeprazole exactly as directed on the label, or as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets.
Use Prilosec OTC (over-the-counter) exactly as directed on the label, or as prescribed by your doctor.
Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you do not understand these instructions.
Shake the oral suspension (liquid) before you measure a dose. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).
If you cannot swallow a capsule whole, open it and sprinkle the medicine into a spoonful of applesauce. Swallow the mixture right away without chewing. Do not save it for later use.
You must dissolve omeprazole powder in a small amount of water. This mixture can either be swallowed or given through a nasogastric (NG) feeding tube using a catheter-tipped syringe.
Use this medicine for the full prescribed length of time, even if your symptoms quickly improve.
OTC omeprazole should be taken for only 14 days in a row. It may take 1 to 4 days before your symptoms improve. Allow at least 4 months to pass before you start a new 14-day course of treatment.
Call your doctor if your symptoms do not improve, or if they get worse.
Some conditions are treated with a combination of omeprazole and antibiotics. Use all medications as directed.
This medicine can affect the results of certain medical tests. Tell any doctor who treats you that you are using this medicine.
Store at room temperature away from moisture and heat.
What happens if I miss a dose?
Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
What to avoid
Omeprazole can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, call your doctor before using anti-diarrhea medicine.
Omeprazole side effects
Get emergency medical help if you have signs of an allergic reaction to omeprazole: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Stop using this medicine and call your doctor at once if you have:
severe stomach pain, diarrhea that is watery or bloody;
new or unusual pain in your wrist, thigh, hip, or back;
kidney problems - fever, rash, nausea, loss of appetite, joint pain, urinating less than usual, blood in your urine, weight gain;
low magnesium - dizziness, irregular heartbeats, feeling jittery, muscle cramps, muscle spasms, cough or choking feeling; or
new or worsening symptoms of lupus - joint pain, and a skin rash on your cheeks or arms that worsens in sunlight.
Taking omeprazole long-term may cause you to develop stomach growths called fundic gland polyps. Talk with your doctor about this risk.
If you use this medicine for longer than 3 years, you could develop a vitamin B-12 deficiency. Talk to your doctor about how to manage this condition if you develop it.
Common omeprazole side effects may include:
fever (especially in children);
stomach pain, gas;
nausea, vomiting, diarrhea; or
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What other drugs will affect omeprazole?
Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.
Tell your doctor about all your current medicines. Many drugs can affect omeprazole, especially:
a diuretic or "water pill"; or
This list is not complete and many Other drugs may interact with omeprazole. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.
Frequently asked questions
- What foods should I avoid when taking omeprazole?
- When is the best time to take omeprazole, before or after a meal?
- Nexium vs Prilosec: What's the difference between them?
More about omeprazole
- Side Effects
- During Pregnancy or Breastfeeding
- Dosage Information
- Patient Tips
- Drug Images
- Drug Interactions
- Compare Alternatives
- Support Group
- Pricing & Coupons
- 333 Reviews
- Drug class: proton pump inhibitors
- Advanced Reading
- Omeprazole Delayed-Release Capsules and Tablets (OTC)
- Omeprazole Orally-Disintegrating Tablets
- Omeprazole Delayed-Release Capsules
- Omeprazole Powder for Oral Suspension
Related treatment guides
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use omeprazole only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
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