Prilosec (Omeprazole)

Generic Name:Omeprazole

Omeprazole is a drug used to treat stomach acid problems.

It comes as both a prescription and over-the-counter (OTC) medicine.

Prescription omeprazole is given to help symptoms of gastroesophageal reflux disease (GERD), a condition where stomach acid flows backwards and causes heartburn or injury to the esophagus, and other problems caused by too much stomach acid.

It’s also used to treat and prevent gastric ulcers caused by Helicobacter pylori (H. pylori) and to help a damaged esophagus heal.

OTC omeprazole is used to treat heartburn that occurs at least two or more days a week.

Omeprazole is in a class of medicines called proton-pump inhibitors. It works by lowering the amount of acid that’s made in the stomach.

The U.S. Food and Drug Administration (FDA) approved omeprazole in 1989. It’s marketed as Prilosec by AstraZeneca Pharmaceuticals.

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What is Prilosec (Omeprazole) used for?

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What is the most important information I should know about Prilosec (Omeprazole)?

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 are also allergic to medicines like omeprazole, such as esomeprazole, lansoprazole, pantoprazole, rabeprazole, Nexium, Prevacid, Protonix, and others;
  • you had breathing problems, kidney problems, or a severe allergic reaction after taking omeprazole in the past; or
  • you also take HIV medication that contains rilpivirine (such as Complera, Edurant, Odefsey, Juluca).

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;
  • unexplained weight loss;
  • nausea or vomiting, stomach pain;
  • liver disease;
  • low levels of magnesium in your blood; or
  • osteoporosis or low bone mineral density (osteopenia).

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.

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Side Effects

What are the side effects of Prilosec (Omeprazole)?

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using omeprazole 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;
  • seizure (convulsions);
  • 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 omeprazole 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 side effects may include:

  • cold symptoms such as stuffy nose, sneezing, sore throat (especially in children);
  • fever (especially in children);
  • stomach pain, gas;
  • nausea, vomiting, diarrhea; or
  • headache.

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.

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Pregnancy & Breastfeeding

Can I take Prilosec (Omeprazole) if I’m pregnant or breastfeeding?

Ask a doctor before using this medicine if you are pregnant or breastfeeding.

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What drugs and food should I avoid while taking Prilosec (Omeprazole)?

This medicine 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.

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Dosage Guidelines & Tips

How to take Prilosec (Omeprazole)?

Use Prilosec (Omeprazole) exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

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 omeprazole.

Store at room temperature away from moisture and heat.

What should I do if I missed a dose of Prilosec (Omeprazole)?

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.

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Overdose Signs

What happens if I overdose on Prilosec (Omeprazole)?

If you think you or someone else may have overdosed on: Prilosec (Omeprazole),  call your doctor or the Poison Control center
(800) 222-1222
If someone collapses or isn't breathing after taking Prilosec (Omeprazole), call 911
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What to Expect

Once you start taking Prilosec, you should begin feeling better within two to three days. It can take up to four weeks for prescription omeprazole to work completely.

Tell your doctor if you don’t notice any changes after about two weeks. Your physician may want to switch you to a different medicine.

OTC Prilosec should be taken for 14 days in a row. Don’t take it for longer than two weeks without checking with a doctor.

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Additional Dosage Information

Your dosage will depend on your medical condition and the formulation of Prilosec you use.

Dosages are typically lower for children and individuals with liver problems.

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Secondary Uses

Prilosec is sometimes also used off-label for:

  • Barrett’s esophagus
  • Infants with GERD
  • Other types of ulcers
  • Preventing aspiration before surgery

Talk to your doctor before using Prilosec to treat any condition that it’s not prescribed for.

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Medical Disclaimer

Drugs A-Z provides drug information from Everyday Health and our partners, as well as ratings from our members, all in one place. Cerner Multum™ provides the data within some of the Overview, Uses, Warnings, Side Effects, Pregnancy, Interactions, Dosage, Overdose, and Images sections. The information within all other sections is proprietary to Everyday Health.