Prilosec (Omeprazole) - Oral

Additional Content Provided and Reviewed by IBM Micromedex

What Is Prilosec?

Prilosec (omeprazole) is a prescription and over-the-counter (OTC) proton pump inhibitor (PPI) that treats stomach and esophagus problems such as acid reflux, gastroesophageal reflux disease (GERD), erosive esophagitis, peptic ulcer disease (PUD), and heartburn.

It alleviates symptoms by preventing the production of hydrochloric acid in your stomach. In turn, acid is unable to irritate the linings of the digestive system.

Prilosec is available as delayed-release capsules/tablets (omeprazole) and an oral suspension (omeprazole magnesium) created by mixing powder packets with water. OTC formulations are available as delayed-release tablets and orally disintegrating delayed-release tablets.

Drug Facts

  • Generic Name: Omeprazole
  • Brand Name(s): Prilosec
  • Drug Availability: Prescription, over the counter
  • Therapeutic Classification: Proton pump inhibitor
  • Available Generically: Yes
  • Controlled Substance: N/A
  • Administration Route: Oral
  • Active Ingredient: Omeprazole
  • Dosage Form(s): Tablet, powder, capsule, packet

What Is Prilosec Used For?

Approved uses of Prilosec vary in its prescription and OTC forms, even though both forms have the same active ingredient.

Prescription Prilosec treats the most severe consequences of acid irritation.

The Food and Drug Administration (FDA) has approved Prilosec for:

  • GERD in adults and children
  • Treatment of H. pylori infection in patients with a peptic ulcer when combined with antibiotics
  • Short-term treatment of gastric ulcer in adults
  • Short-term treatment of erosive esophagitis in adults and children
  • Maintenance of healing of erosive esophagitis in adults and children
  • Pathological hypersecretory conditions, such as  Zollinger-Ellison syndrome, in adults
  • Short-term treatment of peptic ulcer disease in adults

OTC forms help relieve symptoms of frequent heartburn that occur at least two days per week.

How to Take Prilosec

Generally, you can take Prilosec with or without food. However, to maximize its benefits, take it with a glass of water 30 to 60 minutes before a meal. With this method of use, the drug will be present in the body and prepared to prevent acid release and its symptoms.

Swallow tablet and capsule formulations whole; never crush or chew them. You can also open the capsules and sprinkle the contents on soft food or swallow the contents with a spoonful of applesauce. For orally disintegrating tablets, you can either swallow them whole with water or let them dissolve in your mouth with no water required.

All dosage forms are typically taken once per day or as needed depending on your condition. Prescription Prilosec use ranges from two to eight weeks (or more) at the prescriber’s discretion. However, the FDA does not recommend taking OTC formulations for longer than 14 days. You may repeat 14-day treatment periods at four-month intervals.

Follow the drug label instructions from your prescriber to get the most optimal results.

Storage

Store all forms of Prilosec at room temperature in a dry place. Do not store in the bathroom or kitchen. Containers should be closed tightly and kept away from direct sunlight.

Off-Label Uses

There are instances where Prilosec may be prescribed for reasons other than what has been approved by the FDA. This is known as off-label use.

Scientific evidence has shown that Prilosec can be beneficial for:

  • Aspiration prevention: Your healthcare provider might prescribe you to take Prilosec the night before surgery and the morning of surgery to reduce the risk of aspiration during anesthesia. Aspiration is the medical term for when something (e.g., food, saliva, or stomach contents) enters your airways or lungs by accident.  
  • Treatment of Barrett's esophagus
  • Treatment of dyspepsia (idiopathic or non-ulcer)

How Long Does Prilosec Take to Work?

It may take a few days to see any changes in your symptoms. Be sure to take the medication as directed to maximize its effects.

What Are the Side Effects of Prilosec?

This is not a complete list of side effects, and others may occur. A medical professional can advise you on side effects. If you experience other effects, contact your pharmacist or a medical professional. You may report side effects to the FDA at www.fda.gov/medwatch or 1-800-FDA-1088.

Common Side Effects

Prilosec tends to be well tolerated in both adults and children. However, it may cause side effects.

The most common side effects are: 

  • Headache
  • Stomach pain
  • Diarrhea
  • Nausea and vomiting 
  • Gas

Severe Side Effects

Life-threatening side effects from PPIs are rare.

However, some symptoms are severe and should not be taken lightly. Get medical help right away if you experience symptoms such as:

  • Shortness of breath
  • Seizures
  • Dizziness
  • Muscle weakness
  • Dark urine
  • Lack of appetite
  • Bone pain

Long-Term Side Effects

OTC Prilosec is intended to be taken for only a few weeks (14 days), and prescription forms are to be taken as directed and advised by your healthcare provider.

Recent studies regarding long-term use of Prilosec and other PPIs have shown potential side effects:

  • Low vitamin B12 levels: Prilosec can interfere with the absorption of vitamin B12 from food in the body. Vitamin B12 is a nutrient that is important for the functioning of the brain and nervous system. 
  • Low magnesium levels: Although rare, low magnesium levels have been reported in people taking PPIs for three months or more. Magnesium is a nutrient that is important for the health of the body. Patients on multiple medications that may cause low levels of magnesium (e.g., diuretics) while on Prilosec may need their magnesium levels monitored more closely. They may also need to take magnesium supplements.
  • Bone fractures: Using Prilosec daily for a year or longer can increase the potential for bone fractures (a crack or a break in a bone). Patients with a history of hip fracture or osteoporosis may need a lower doses based on risk vs. benefit. 
  • Infection: Although not fully understood, it is thought that the prevention of gastric acids capable of killing Clostridium difficile (C. difficile) spores can increase the risk of infection. Patients with persistent diarrhea that does not improve while on PPIs could potentially have C. difficile-associated diarrhea.

Report Side Effects

Prilosec may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting Program or by phone (1-800-332-1088).

Dosage: How Much Prilosec Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

For oral dosage forms (capsules, delayed-release capsules or suspension, or tablets):

To treat duodenal ulcers:

  • Adults—20 milligrams (mg) once a day before a meal. Your doctor may adjust your dose as needed.
  • Children—Use and dose must be determined by your doctor.

To treat duodenal ulcers with H. pylori:

  • Adults—20 or 40 milligrams (mg) one, two, or three times a day before a meal. The dose is usually taken together with clarithromycin or clarithromycin plus amoxicillin. Your doctor may adjust your dose as needed.
  • Children—Use and dose must be determined by your doctor.

To treat erosive esophagitis:

  • Adults—20 milligrams (mg) once a day before a meal. Your doctor may adjust your dose as needed.
  • Children—Use and dose must be determined by your doctor.

To treat erosive esophagitis caused by acid-mediated GERD:

  • Adults and children 17 years of age and older—20 milligrams (mg) once a day before a meal.
  • Children 1 to 16 years of age—Dose is based on body weight and must be determined by your doctor. The dose is usually 5 to 20 mg once a day before a meal.
  • Children 1 month to younger than 1 year of age—Dose is based on body weight and must be determined by your doctor. The dose is usually 2.5 to 10 mg once a day before a meal.
  • Children younger than 1 month of age—Use and dose must be determined by your doctor.

To treat gastric ulcers:

  • Adults—40 milligrams (mg) once a day before a meal. Your doctor may adjust your dose as needed.
  • Children—Use and dose must be determined by your doctor.

To treat gastroesophageal reflux disease (GERD):

  • Adults—20 milligrams (mg) once a day before a meal. Your doctor may want you to take omeprazole for more than 8 weeks for certain conditions.
  • Children 1 year of age and older—Dose is based on body weight and must be determined by your doctor. The dose is usually 5 to 20 mg once a day before a meal.
  • Children younger than 1 year of age—Use and dose must be determined by your doctor.

To treat Zollinger-Ellison syndrome:

  • Adults—60 milligrams (mg) once a day before a meal. Your doctor may adjust your dose as needed.
  • Children—Use and dose must be determined by your doctor.

For oral dosage form (powder for suspension):

To prevent upper gastrointestinal tract bleeding in seriously ill patients:

  • Adults—The first day: 40 milligrams (mg) for the first dose, then after 6 to 8 hours, a second 40 mg dose. After the first day: 40 mg once a day for up to 14 days.
  • Children—Use and dose must be determined by your doctor.

To treat duodenal ulcer:

  • Adults—20 milligrams (mg) once a day for 4 to 8 weeks.
  • Children—Use and dose must be determined by your doctor.

To treat gastric ulcers:

  • Adults—40 milligrams (mg) once a day for 4 to 8 weeks.
  • Children—Use and dose must be determined by your doctor.

To treat gastroesophageal reflux disease (GERD) for erosive esophagitis:

  • Adults—20 milligrams (mg) once a day for 4 to 8 weeks.
  • Children—Use and dose must be determined by your doctor.

Modifications

There are no adequate studies on people who are pregnant using this medication. So far, available data have not shown any increased risk of major birth defects following omeprazole use during pregnancy. As with any medication, you should consult with your healthcare provider if you are pregnant or plan on becoming pregnant.

Omeprazole is safe to take while breastfeeding. Low levels of Prilosec have been found in breast milk, but not enough to be harmful to the baby.

Children generally follow weight-based dosing. As with adults, children with swallowing difficulties can use the oral suspension or take the sprinkled contents of the capsule with soft food.

Missed Dose

If you miss a dose, take it as soon as you think about it. If it is almost time for your next dose, skip the missed dose and continue your regular intake schedule. Do not take extra doses or multiple doses at the same time.

Overdose: What Happens If I Take Too Much Prilosec?

Prilosec overdose is possible, but symptoms are usually temporary and can be similar to side effects seen with standard dosage.

Overdose symptoms of Prilosec may include: 

  • Blurred vision
  • Confusion
  • Headache
  • Increased sweating

What Happens If I Overdose On Prilosec?

If you think you or someone else may have overdosed on Prilosec (omeprazole), call a healthcare provider or the Poison Control Center (1-800-222-1222).

If someone collapses or isn't breathing after taking omeprazole, call 911 immediately.

Precautions

Drug Content Provided and Reviewed by IBM Micromedex

It is important that your doctor check your or your child's progress at regular visits. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to take it. Blood, urine, and other laboratory tests may be needed to check for unwanted effects. If your or your child's condition does not improve, or if it becomes worse, check with your doctor.

Tell your doctor if you have Asian relatives, such as Filipino, Chinese, Japanese, Korean, or Taiwanese. You may need a lower dose of this medicine to treat erosive esophagitis.

Do not use omeprazole if you are also using medicines containing rilpivirine (Edurant®, Complera®). Using these medicines together may cause unwanted side effects.

This medicine is sometimes given together with other medicines to treat ulcers. Be sure you understand about the risks and proper use of any other medicine your doctor gives you or your child together with omeprazole.

Omeprazole may cause a serious type of allergic reaction when used in patients with conditions treated with antibiotics. Call your doctor right away if you or your child has itching, trouble breathing or swallowing, or any swelling of your hands, face, or mouth.

Check with your doctor right away if you or your child has a change in frequency of urination or amount of urine, blood in the urine, fever, joint pain, loss of appetite, skin rash, swelling of the body, feet, or ankles, unusual tiredness or weakness, or unusual weight gain after receiving this medicine. These could be symptoms of a serious kidney problem called acute tubulointerstitial nephritis.

Taking this medicine for a long time may make it harder for your body to absorb vitamin B12. Tell your doctor if you have concerns about vitamin B12 deficiency.

Serious stomach conditions may occur while taking this medicine alone or together with antibiotics. Check with your doctor immediately if you or your child has stomach cramps, bloated feeling, watery and severe diarrhea which may also be bloody sometimes, fever, nausea or vomiting, or unusual tiredness or weakness.

This medicine may increase your risk of having fractures of the hip, wrist, and spine. This is more likely if you are 50 years of age and older, if you receive high doses of this medicine, or use it for one year or more.

This medicine may cause hypomagnesemia (low magnesium in the blood). This is more likely to occur if you are taking this medicine for more than 1 year, or if you are taking this medicine together with digoxin (Lanoxin®) or certain diuretics or "water pills". Check with your doctor right away if you have convulsions (seizures), fast, racing, or uneven heartbeat, muscle spasms (tetany), tremors, or unusual tiredness or weakness.

Cutaneous or systemic lupus erythematosus may occur or get worse in patients receiving a PPI. Call your doctor right away if you have joint pain or a skin rash on your cheeks or arms that gets worse when exposed to the sun.

This medicine may increase your risk for fundic gland polyps (abnormal tissue growth in the upper part of your stomach). This is more likely if you are receiving this medicine for more than 1 year. Talk to your doctor if you have concerns.

Do not stop taking this medicine without first checking with your doctor, or unless told to do so by your doctor.

Make sure any doctor or dentist who treats you knows that you are using this medicine. You may need to stop using this medicine several days before you have medical tests.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription (eg, atazanavir, nelfinavir, Reyataz®, Viracept®) or nonprescription (over-the-counter [OTC]) medicines and herbal (eg, St. John's wort) or vitamin supplements.

What Are Reasons I Shouldn’t Take Prilosec?

There are cases in which Prilosec use may not be recommended.

You should not take Prilosec if you have had allergic reactions to any ingredients of the medication that cause:

People with liver disease should use caution when taking this medication, as it can take longer to clear from the body and increase the potential for its side effects.

Additionally, long-term and/or high-dose use of PPIs has been associated with a higher risk of bone issues of the hip, spine, and wrist. PPI use may not be recommended if you have a history of bone fractures, osteopenia, or osteoporosis.

What Other Medications Interact With Prilosec?

Prilosec has many drug interactions, so it is important to share what other medications you are taking with your healthcare provider. Prilosec suppresses acid production in the body, which can interfere with how other medications work. 

When taken together, Prilosec may increase the absorption of the following medications, creating a greater risk of toxicity:

Prilosec may decrease the absorption of the following medications when used in combination, making them less effective: 

  • Alendronate (bone medication)
  • Capecitabine (chemotherapy)
  • Cefpodoxime (antibacterial)
  • Clozapine (antipsychotic)
  • Doxycycline (antibacterial)
  • Atazanavir and nelfinavir (antiretroviral therapy)

Drugs that induce CYP2C19 or CYP3A4 enzymes, such as St. John’s wort and rifampin, may reduce how well Prilosec works when used together. Avoid using Prilosec in combination with St. John’s wort or rifampin.

Discuss any other medications you are taking with your healthcare provider. They will determine if your treatment regimen needs to be changed.

What Medications Are Similar?

Two other PPIs, Prevacid (lansoprazole) and Nexium (esomeprazole), are also available over the counter.

There are currently five prescription PPIs that are similar to Prilosec:

Each medication works the same in the body, but they all have unique characteristics. Differences in the medication’s characteristics may drive the decision on which will work best for you as a patient.

For example, some medications work more quickly than others. Prilosec reaches maximum effectiveness within 30 minutes, while other PPI medications may take one to two hours.

Additionally, each PPI has a different concentration in your body system. Lansoprazole and esomeprazole have the highest concentrations, while rabeprazole has the lowest.

Frequently Asked Questions

  • What are common side effects of Prilosec? When should I be concerned?

    Possible side effects of Prilosec include headache, nausea, diarrhea, and abdominal pain. These symptoms are common and are not very concerning. However, if they are bothersome or persistent, you should contact your healthcare provider. 

    More severe and worrisome symptoms include severe dizziness, bone pain, and loss of strength and energy.

  • Will OTC Prilosec work in the same way as the prescription form?

    No, OTC and prescription Prilosec have different treatment targets based on the severity of your condition. It is best to ask your healthcare provider which is more appropriate for you.

  • When taking OTC Prilosec, what should I do after the 14-day treatment period?

    If your symptoms persist after the 14-day treatment period, do not continue taking the medication. Contact your healthcare provider first and discuss your options.

  • How long will it take for my symptoms to improve?

    It may take a few days to see any changes in your symptoms. Be sure to take the medication as directed to maximize its effects.

How Can I Stay Healthy While Taking Prilosec?

Sticking to a medication regimen can be difficult. However, in order to get the maximal benefits of this medication, you must take Prilosec consistently.

Stay on top of your Prilosec treatment by:

  • Setting an alarm to remind you when to take your dose
  • Taking it first thing in the morning before breakfast
  • Using a pill organizer

Treating health conditions does not stop with medication regimens. Taking the initiative to make lifestyle changes can go a long way as well.

Here are some examples of what can help: 

  • Avoid food triggers: Pay attention to what foods or drinks cause symptoms or make them worse. Create a list of those foods and avoid them as much as possible. Examples may include alcohol, pepper, coffee, and tomatoes. 
  • Time your meals: Eating right before lying down or going to bed can irritate your digestive system, as the body is not given time to digest what you just ate. Try to eat at least an hour before you go to bed. 
  • Add exercise: Implementing low-to-moderate exercise for 30 minutes to an hour, three to five days per week, can prevent and relieve symptoms by helping you lose excess weight and promoting good heart health. Walking, jogging, swimming, and yoga are all examples of great exercises.

If you have any questions about side effects, OTC/prescription directions, or general concerns, do not hesitate to contact your healthcare team. They are there to help.

Medical Disclaimer

Verywell Health's drug information is meant for education purposes only and not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare professional. Consult your doctor before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

Was this page helpful?
2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Prilosec prescribing information. Updated December  2016.

  2. Omeprazole. Lexi-Drugs. Hudson, OH: Lexicomp, 2021. http://online.lexi.com/. Updated June 24, 2021.