omeprazole
Omeprazole (Prilosec) is a proton pump inhibitor (PPI). Over-the-counter (OTC) omeprazole (Prilosec) can ease heartburn, while the prescription version can treat gastroesophageal reflux disease (GERD) and other conditions involving too much stomach acid. Omeprazole (Prilosec) is taken by mouth, typically once daily 30 minutes before breakfast. Some of the more common side effects of omeprazole (Prilosec) include headache, stomach pain, and nausea. It's available as both brand name and generic medications.
What is Omeprazole (Prilosec)?
What is Omeprazole (Prilosec) used for?
For adults only:
Heartburn — OTC only
Lower the risk of duodenal ulcer caused by Helicobacter pylori (H. pylori) infection
Other medical conditions that cause too much stomach acid (e.g., Zollinger-Ellison syndrome)
For adults and children:
How Omeprazole (Prilosec) works
Omeprazole (Prilosec) is a proton pump inhibitor (PPI). It lowers the amount of acid in your stomach by blocking the final step of stomach acid production. This helps relieve heartburn and other stomach problems.
Drug Facts
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What are the side effects of Omeprazole (Prilosec)?
Common Side Effects
- Headache (7%)
- Belly pain (5%)
- Nausea (4%)
- Diarrhea (4%)
- Vomiting (3%)
- Passing gas (3%)
- Respiratory system problems (up to 75%)
- Fever (up to 33%)
- Ear infection (up to 22%)
Other Side Effects
- Acid reflux
- Constipation
- Dizziness
- Back pain
- Cough
- Upper respiratory infection (e.g., common cold)
- Rash
- Feeling weak
Serious Side Effects
- Severe stomach pain or diarrhea
- Kidney problems: urinating more or less than usual, fever, poor appetite, blood in urine
- Lupus symptoms: joint pain, skin rash on arms or cheeks that gets worse in the sunlight
- Serious allergic reaction: blistering, peeling, or bleeding skin; fever; chills; trouble breathing; face swelling
Source: DailyMed
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The following side effects have also been reported
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Rare
Back, leg, or stomach pain
bleeding or crusting sores on the lips
blisters
bloody or cloudy urine
chills
continuing ulcers or sores in the mouth
difficult, burning, or painful urination
frequent urge to urinate
general feeling of discomfort or illness
itching, skin rash
joint pain
loss of appetite
muscle aches or cramps
red or irritated eyes
redness, tenderness, itching, burning, or peeling of the skin
sores, ulcers, or white spots on the lips, in the mouth, or on the genitals
unusual bleeding or bruising
unusual tiredness or weakness
Incidence not known
Blistering, peeling, or loosening of the skin
drowsiness
fast, racing, or uneven heartbeat
mood or mental changes
muscle spasms (tetany) or twitching seizures
red skin lesions, often with a purple center
red, irritated eyes
trembling
vomiting
Get emergency help immediately if any of the following symptoms of overdose occur:
Symptoms of overdose
Blurred vision
confusion
dryness of the mouth
flushing
headache
increased sweating
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Pros and cons of Omeprazole (Prilosec)
Pros
Typically few to no noticeable day-to-day side effects
Provides longer-lasting relief than some other heartburn medications
Can use for adults, as well as children with certain medical conditions
Available as over-the-counter and lower-cost generic options
Cons
Interacts with many medications, such as digoxin (Lanoxin) and clopidogrel (Plavix)
Won't provide immediate heartburn relief
Usually taken 30 to 60 minutes before eating a meal for best results
Not recommended for long-term treatment, except for certain conditions, because of risk of serious side effects
Pharmacist tips for Omeprazole (Prilosec)
Swallow the omeprazole (Prilosec) pills whole. Don't chew or crush the pills. Doing so can change how the medication gets absorbed into your body.
If you're taking omeprazole (Prilosec) once daily, it's best to take omeprazole (Prilosec) 30 to 60 minutes before breakfast, on an empty stomach. But if you forget to take it before a meal, just take it as soon as you remember. But if it's almost time for your next scheduled dose, just skip the missed dose and take it at your next scheduled time.
Omeprazole (Prilosec) doesn't provide immediate-relief of heartburn symptoms because it takes some time to work. Your primary care provider (PCP) might recommend that you take antacids with omeprazole (Prilosec) because antacids work faster than PPIs.
Omeprazole (Prilosec) oral capsules: If you can't swallow the capsules, you can open the capsule and sprinkle the pellets inside onto one tablespoon of applesauce. Once mixed, swallow the applesauce right away without chewing or crushing the pellets. You can drink some cool water afterwards to make sure you've swallowed all the medication. Don't save any of the mixture for later, since the medication might not work as well anymore.
Omeprazole (Prilosec) oral granules: Mix and stir the granules with water. You need 5 mL of water for each 2.5 mg packet and 15 mL of water for each 10 mg packet. Wait 2 to 3 minutes. Then, stir and drink the entire dose within 30 minutes of mixing.
Omeprazole (Prilosec) can interact with many medications. For example, taking omeprazole (Prilosec) with warfarin (Coumadin) can raise your risk for bleeds, so your prescriber might need to adjust your dose of wafarin (Coumadin). Let your prescriber or pharmacist know what medications you take or plan to take, including any over-the-counter products and supplements, so they can help you check for interactions.
Tips for over-the-counter omeprazole (Prilosec OTC)
Omeprazole (Prilosec) orally disintegrating tablets: If you can't swallow the oral tablets, you can melt the orally disintegrating tablet on your tongue.
Before using omeprazole (Prilosec), ask your primary care provider (PCP) if this medication is right for you. This is especially true if you experience the following: heartburn for more than 3 months, frequent wheezing, weight loss, nausea, vomiting, or stomach pain. These could be signs of a serious problem that your primary care provider should check out.
Stop taking omeprazole (Prilosec), and speak with your primary care provider if you need this heartburn medication for more than 14 days or if you need more than one course of treatment every 4 months. Also do so if you have the following: heartburn gets worse, rash, joint pain, or diarrhea. There might be some other problem going on that your PCP can help you with.
Get medical help right away if you experience trouble or pain swallowing, bloody vomit, bloody or black stools, heartburn with lightheadedness or sweating, shoulder pain with shortness of breath, or chest pain. These can be symptoms of serious medical conditions, such as stomach bleeding or heart attack, which need to be treated as soon as possible.
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Frequently asked questions about Omeprazole (Prilosec)
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What are the risks and warnings for Omeprazole (Prilosec)?
Omeprazole (Prilosec) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk of hiding symptoms of a more serious problem
Frequent episodes of heartburn can be a symptom of stomach cancer. If your heartburn gets worse or comes back after taking omeprazole (Prilosec), let your primary care provider know. Also contact your primary care provider if you've poor appetite, unexplained weight loss, or weakness along with your heartburn. They can check if there are other serious medical problems going on.
Sudden kidney problems
Some people taking PPIs like omeprazole (Prilosec) have had sudden kidney problems. These problems can happen at any point during treatment. Talk with your primary care provider if you're urinating more or less than usual, feel nauseous or weak, or have a fever, rash, or joint pain. These can be symptoms of kidney problems.
Severe infectious diarrhea
Risk factors: Older people | Recent stay at a hospital or nursing home | People with a weakened immune system (e.g., HIV, cancer)
Some clinical studies showed that PPIs, such as omeprazole (Prilosec), can raise the risk of getting a bacterial infection called Clostridioides difficile (C. diff). This infection can cause severe diarrhea. Your risk is higher if you're over 65 years old, have recently stayed at a hospital or nursing home, or have a weakened immune system. To lower your risk of C. diff diarrhea, take the lowest possible dose of omeprazole (Prilosec) for the shortest amount of time that works well for you. If you experience severe or watery diarrhea, fever, belly pain, loss of appetite, or nausea, let your primary care provider know right away.
Bone fractures
Risk factors: Taking high doses of omeprazole (Prilosec) | Taking omeprazole (Prilosec) for longer than a year | Risk for osteoporosis
PPIs like omeprazole (Prilosec) might raise the risk of bone fractures in the hip, wrist, or spine. Your risk is higher if you take more than one dose of omeprazole (Prilosec) per day or if you take it for more than a year. To prevent the risk of bone fracture, take the lowest possible dose of omeprazole (Prilosec) for the shortest amount of time for your symptoms. If you've had bone fractures before or have osteoporosis (weak bones), talk to your prescriber about your risk before using this medication.
Skin reactions
PPIs, such as omeprazole (Prilosec), have rarely caused serious skin reactions. These reactions include Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). Symptoms can include fever, body aches, rash, peeling skin, painful blisters, and swelling of the face. If you notice any of these symptoms, get medical help immediately.
Lupus
Some people taking PPIs like omeprazole (Prilosec) developed new or worsening lupus, a condition where your immune system attacks your own body. Lupus symptoms can occur any time during treatment with omeprazole (Prilosec). Some typical symptoms include joint pain or rash, but they often improve within 1 to 3 months of stopping this medication. If you experience any lupus symptoms while taking omeprazole (Prilosec), stop the medication and contact your primary care provider.
Low vitamin B12 and magnesium levels
Risk factor: Long-term use | Taking medications that can lower magnesium levels
Using acid-lowering medications like omeprazole (Prilosec) for a long period of time can cause your vitamin B12 levels to drop. Omeprazole (Prilosec) lowers the amount of acid in your stomach, which is needed for vitamin B12 absorption. If you've been taking this medication for longer than 3 years, or if you have symptoms of vitamin B12 deficiency (e.g., dizziness, muscle weakness, pale skin, tiredness, tingling in arms or legs), talk to your prescriber.
Taking omeprazole (Prilosec) can also lower your magnesium levels. This can happen 3 months after taking omeprazole (Prilosec), but it's more likely after a year of treatment. Low magnesium levels can sometimes lead to other electrolyte problems. You're at risk for low magnesium levels if you take other medications that can affect electrolyte levels, such as digoxin (Lanoxin) or water pills. Your primary care provider might check your blood during treatment with omeprazole (Prilosec) to make sure your electrolyte levels are in the normal range. Watch for symptoms of electrolyte problems like irregular heart rate, muscle cramps, and tremors. Let your primary care provider know right away if they occur.
Interaction with other medications
Some medications can interfere with how your body gets rid of omeprazole (Prilosec). Depending on if they boost or block how omeprazole (Prilosec) gets removed, the medications can affect the amount of omeprazole (Prilosec) in your body, how well it works, and the risk of side effects. For example, St. John’s wort and rifampin (Rifadin) can lower the amount of omeprazole (Prilosec) in your body and cause the medication to not work as well. Avoid these medications while taking omeprazole (Prilosec).
Omeprazole (Prilosec) can also interfere with how other medications work. An important medication to avoid with omeprazole (Prilosec) is clopidogrel (Plavix). Omeprazole (Prilosec) causes clopidogrel (Plavix) to not work as well, which raises the risk of blood clots. In addition, omeprazole (Prilosec) can raise the risk of methotrexate toxicity when taken together with methotrexate.
Inaccurate lab work
Omeprazole (Prilosec) can get in the way of certain tumor screenings, which can lead to inaccurate results. Talk with your primary care provider or radiologist about your medication history before getting any testing done. In some cases, your care team might ask you to temporarily stop omeprazole (Prilosec) 2 weeks before your blood work.
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Omeprazole (Prilosec) dosage forms
Typical dosing for Omeprazole (Prilosec)
Omeprazole (Prilosec) is available both over the counter (OTC) and by prescription. The OTC strength is 20 mg, and the prescription strengths are 10 mg, 20 mg, and 40 mg.
The dosing for adults is listed below. Dosing for children will depend on the child’s weight, age, and the reason they're taking the medication. In general, your child's provider will determine the dosage your child needs to take.
OTC dosing (adults):
Heartburn: The typical dose is 20 mg by mouth once daily in the morning for 2 weeks.
Prescription dosing (adults):
Stomach or duodenal ulcer: The typical dose is 20 mg or 40 mg by mouth once daily for 1 to 2 months, depending on the type of ulcer.
Gastroesophageal reflux disease (GERD): The typical dose is 20 mg by mouth once daily for up to 1 month.
Treatment of inflamed esophagus due to GERD: The typical dose is 20 mg by mouth once daily for 1 to 2 months.
Maintenance of healing of inflamed esophagus due to GERD: The typical dose is 20 mg by mouth once daily. Your dose might differ if you have liver problems or if you're of Asian descent.
H. pylori triple therapy: The typical dose is 20 mg by mouth twice daily for 10 days. It's usually taken together with amoxicillin and clarithromycin.
H. pylori dual therapy: The typical dose is 40 mg by mouth once daily for 2 weeks. It's usually taken together with clarithromycin.
Medical conditions that cause too much stomach acid: The typical starting dose is 60 mg by mouth once daily. The maximum dose is 120 mg three times daily.
Prescription dosing (children): Your child's dose will depend on their condition and body weight.
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Interactions between Omeprazole (Prilosec) and other drugs
More on Omeprazole (Prilosec) interactions
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
- Rilpivirine
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Abametapir
- Acalabrutinib
- Amphetamine
- Atazanavir
- Benzphetamine
- Bosutinib
- Capecitabine
- Cilostazol
- Citalopram
- Clopidogrel
- Clorazepate
- Conivaptan
- Dacomitinib
- Dasabuvir
- Dasatinib
- Delavirdine
- Dextroamphetamine
- Elagolix
- Erlotinib
- Escitalopram
- Eslicarbazepine Acetate
- Fosnetupitant
- Gefitinib
- Indinavir
- Ketoconazole
- Ledipasvir
- Lisdexamfetamine
- Methamphetamine
- Methotrexate
- Mycophenolate Mofetil
- Nelfinavir
- Neratinib
- Netupitant
- Nilotinib
- Octreotide
- Ombitasvir
- Paritaprevir
- Pazopanib
- Pexidartinib
- Ritonavir
- Saquinavir
- Secretin Human
- Selpercatinib
- Sunitinib
- Tacrolimus
- Velpatasvir
- Vismodegib
- Voriconazole
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Armodafinil
- Carbamazepine
- Digoxin
- Disulfiram
- Fluconazole
- Ginkgo Biloba
- Iron
- Levothyroxine
- Raltegravir
- St John's Wort
- Tipranavir
- Triazolam
- Warfarin
How much does Omeprazole (Prilosec) cost?
Omeprazole (Prilosec) contraindications
History of allergy to PPIs
People receiving Edurant (rilpivirine) or rilpivirine-containing medications (e.g., Complera)
What are alternatives to Omeprazole (Prilosec)?
For adults only:
Heartburn — OTC only
Lower the risk of duodenal ulcer caused by Helicobacter pylori (H. pylori) infection
Other medical conditions that cause too much stomach acid (e.g., Zollinger-Ellison syndrome)
For adults and children:
Heartburn — OTC only
Lower the risk of stomach ulcer due to nonsteroidal anti-inflammatory drugs (NSAID)
Lower the risk of duodenal ulcer caused by Helicobacter pylori (H. pylori) infection
Other medical conditions that cause too much stomach acid (e.g., Zollinger-Ellison syndrome)
Frequent heartburn (2 or more days a week) - OTC only
Lower the risk of duodenal ulcer caused by Helicobacter pylori (H. pylori) infection
Lower the risk of stomach ulcer due to nonsteroidal anti-inflammatory drugs (NSAID)
Other medical conditions that cause too much stomach acid (e.g., Zollinger-Ellison syndrome)
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References
Best studies we foundAmerican Cancer Society. (2021). Signs and symptoms of stomach cancer.
Ankar, A., et al. (2022). Vitamin B12 deficiency. StatPearls.
Apotex Corp. (2023). OMEPRAZOLE capsule, delayed release [package insert]. DailyMed.
Bidaki, R., et al. (2017). Accidental chronic poisoning with methotrexate; report of two cases. Emergency.
Centers for Disease Control and Prevention. (2022). Lupus symptoms.
Centers for Disease Control and Prevention. (2022). What is C. diff?
Covis Pharma US, Inc. (2022). PRILOSEC- omeprazole magnesium granule, delayed release [package insert]. DailyMed.
Gerson, L.B. (2012). Treatment of Gastroesophageal Reflux Disease During Pregnancy. Gastroenterology and Hepatology.
MedlinePlus. (2016). Esophagus disorders.
MedlinePlus. (2020). Stevens-Johnson syndrome/toxic epidermal necrolysis.
Katz, P.O. (2022). ACG Clinical Guideline for the Diagnosis and Management of Gastroesophageal Reflux Disease. The American Journal of Gastroenterology.
Meijer, Inc. (2022). 24 HR OMEPRAZOLE- omeprazole tablet, delayed release [package insert]. DailyMed.
National Cancer Institute Dictionary of Cancer Terms. (n.d.). Immunocompromised.
Office of Dietary Supplements. (2021). Vitamin B12. National Institutes of Health.
Poly, T.N., et al. (2022). Proton Pump Inhibitor Use and Risk of Gastric Cancer: Current Evidence from Epidemiological Studies and Critical Appraisal. Cancers.
Sandhu, D.S., et al. (2018). Current Trends in the Management of Gastroesophageal Reflux Disease. Gut and Liver.
Smith, J.P. (2017). Gastrin and Gastric Cancer. Cellular and Molecular Gastroenterology and Hepatology.
United Natural Foods, Inc. (2023). EQUALINE OMEPRAZOLE- omeprazole tablet, delayed release [package insert]. DailyMed.
Walgreen Company. (2023). OMEPRAZOLE- omeprazole tablet, orally disintegrating, delayed release [package insert]. DailyMed.
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