Uses

What is omeprazole used for?

Omeprazole is used to treat heartburn and certain other conditions caused by too much acid in the stomach.

Omeprazole may also be used for other conditions as determined by your healthcare provider.

How does omeprazole work (mechanism of action)?

Omeprazole works by decreasing the amount of acid your stomach makes.

How is omeprazole supplied (dosage forms)?

Omeprazole is available as Prilosec, Prilosec OTC, and generic omeprazole in the following dosage forms that are taken by mouth.

  • 10 mg delayed-release oral capsules
  • 20 mg delayed-release oral capsules
  • 40 mg delayed-release oral capsules
  • 20 mg delayed-release oral tablets
  • 20 mg delayed-release orally disintegrating tablets
  • 2.5 mg packets of powder for delayed-release oral suspension
  • 10 mg packets of powder for delayed-release oral suspension

How should I store omeprazole?

Omeprazole should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C), for shorter periods of time, such as when transporting it. Store in a cool, dry place.

Do not remove orally disintegrating tablets from the blister pack until ready to take. 

Side Effects

What are the most common side effects of omeprazole?

The most common side effects of omeprazole are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

  • Headache
  • Stomach pain
  • Nausea
  • Diarrhea
  • Vomiting
  • Gas
  • Infection in the nose or throat (children age 1 to 16 years)
  • Fever (children age 1 to 16 years)

There may be other side effects of omeprazole that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of omeprazole?

While less common, the most serious side effects of omeprazole are described below, along with what to do if they happen.

Kidney problems. A type of kidney problem called acute tubulointerstitial nephritis can happen at any time during treatment with omeprazole. If you notice a decrease in the amount of your urine or see blood in your urine, call your doctor right away. 

Antibiotic-associated Diarrhea. An overgrowth of germs called Clostridioides difficile, or “C. diff,” can happen in your gut during treatment with omeprazole. Call your healthcare provider right away if you have any of the following symptoms of this condition.

  • Watery diarrhea
  • Diarrhea that does not go away
  • Blood in your stool (poop)
  • Severe stomach cramps
  • Fever that starts after you start or finish the medicine

Severe Skin Reactions. Omeprazole can cause severe skin reactions, such as Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN), that can lead to death if not treated. If you develop a rash, stop omeprazole and call your healthcare provider right away. Get emergency help right away if you have any of the following symptoms of SJS or TEN.

  • Painful red or purple skin that looks burned and peels off
  • Flat red rash or blisters on your skin, mouth, nose, and genitals
  • Red, painful, watery eyes

Severe Allergic Reaction called DRESS. Omeprazole can cause a specific type of allergic reaction called DRESS. DRESS stands for Drug Reaction with Eosinophilia and Systemic Symptoms. It is also sometimes called multi-organ hypersensitivity. This is a reaction that can affect multiple parts of the body including your liver, kidneys, and heart. Stop using the medicine and get help right away if you have any of the following symptoms of this serious allergic reaction.

  • Skin rash or pale red bumps on the skin called hives
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Shortness of breath
  • Swelling in your feet, ankles, or legs
  • Dark colored urine
  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Lupus. Some medicines, such as omeprazole, can cause certain types of lupus or cause worsening of lupus you already have. Lupus is an autoimmune disorder where your immune cells attack other cells or organs in your body. Tell your provider right away if you have new or worsening joint pain or a rash on your arms or cheeks.

Vitamin B-12 deficiency. Omeprazole can cause you to absorb less vitamin B-12 than usual, which can cause low vitamin B-12 levels. You have a higher risk of this if you take omeprazole for a long time (3 years or longer). Stop using omeprazole and call your healthcare provider if you have any of the following symptoms.

  • Sore tongue
  • Weakness 
  • Tingling or numbness in your hands or feet

Hypomagnesemia. Omeprazole can cause low magnesium levels, also known as hypomagnesemia, which can be serious. Decreased magnesium levels can cause seizures or heart rhythm problems. Some people have a higher risk of this, including people who take the omeprazole for a long time or those that take other medicines that can cause low magnesium. Stop using omeprazole and call your healthcare provider if you have any of the following symptoms.

  • Changes in your heart rate or rhythm, such as fast or skipping heartbeat
  • Dizziness 
  • Muscle spasms
  • Seizures 

Bone loss and fractures. Omeprazole may cause bone loss and increase your risk for fractures. The risk is higher in older adults and people taking omeprazole for a long time or taking a high dose.

Severe Allergic Reactions. Omeprazole may cause allergic reactions, which can be serious. Stop using omeprazole and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Warnings & Precautions

Who should not use omeprazole?

Allergies to Ingredients. People who are allergic to any of the following should not use omeprazole.

  • Omeprazole
  • Prilosec
  • Prilosec OTC
  • Any other medicine known as a proton pump inhibitor
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific omeprazole products they stock.

Drug Interactions. Omeprazole should not be taken while you are using certain other medicines. Before taking omeprazole, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

What should I know about omeprazole before using it?

Do not take omeprazole unless it has been prescribed to you by a healthcare provider. Take it as prescribed.

Do not share omeprazole with other people, even if they have the same condition as you. It may harm them.

Keep omeprazole out of the reach of children.

Do not chew, cut, or crush omeprazole.

Take omeprazole before a meal.

Antacids may be taken with omeprazole if needed.

If you are having difficulty swallowing the omeprazole capsule, you may open them and sprinkle the contents on 1 tablespoon of applesauce. Swallow the applesauce right away. Don’t mix the contents with any other food.

Omeprazole should not be used for immediate relief of heartburn. It may take 1 to 4 days for the medicine to fully work.

What should I tell my healthcare provider before using omeprazole?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if omeprazole is right for you.

Current and Past Health Conditions. Tell your healthcare provider if you have any of the following.

Other Medicines and Supplements. Omeprazole may interact with other medicines and supplements. Before using omeprazole, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how omeprazole could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant. Your healthcare provider will advise you if you should take omeprazole while you are pregnant or trying to get pregnant. 

Breastfeeding. Do not take omeprazole while you are breastfeeding. Omeprazole can pass into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed.

Interactions

Does omeprazole interact with foods or drinks?

Take omeprazole before meals.

It is unknown if drinking alcohol will affect omeprazole.

Does omeprazole interact with other medicines (drug interactions)?

Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before using omeprazole.

  • Clopidogrel (Plavix), which is a blood thinner used to prevent or treat blood clots
  • Cilostazol (Pletal), which is a medicine used to decrease the symptoms of intermittent claudication
  • Citalopram, which is a medicine used to treat depression
  • Methotrexate (Trexall and others)
  • Digoxin (Lanoxin), which is a medicine used to treat irregular heartbeat and some types of heart failure
  • Warfarin, which is used as a blood thinner
  • Certain antiretroviral medicines, such as rilpivirine (Edurant), nelfinavir (Viracept), or saquinavir (Invirase), which are used for HIV or AIDS
  • St. John’s Wort
  • Rifampin, which is a medicine commonly used to treat an infection called tuberculosis

Some other medicines may alter the blood levels of omeprazole, and vice versa. Tell your healthcare provider about all medicines that you take or have recently taken. Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

Omeprazole may affect the absorption of some other medicines. Tell your healthcare provider about all medicines that you take or have recently taken.

This may not be a complete list of medicines that can interact with omeprazole. Always check with your healthcare provider.

Does Omeprazole interact with other drugs you are taking?
Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much omeprazole?

If you or someone else has used too much omeprazole, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of omeprazole?

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 only take the next dose. Do not take double or extra doses.