iCliniq logo

Ask a Doctor Online Now

HomeHealth articlesomeprazoleOmeprazole - Uses | Dosage | Side Effects | Drug Interactions | Precautions


Verified dataVerified data

4 min read


Omeprazole works by decreasing stomach acid because of this, it is used in conditions like gastroesophageal reflux disease, indigestion, and stomach ulcers caused by the bacteria H. pylori.

Published At February 9, 2019
Reviewed AtAugust 2, 2023

Overview of Omeprazole

Omeprazole belongs to the proton pump inhibitors group of drugs. It works by decreasing stomach acid because of which, it is used in conditions like gastroesophageal reflux disease (GERD), indigestion, and stomach ulcers caused by bacteria Helicobacter pylori. It relieves symptoms caused by an increase in stomach acids like heartburn, abdominal pain, and a group of patients with persistent cough due to acid reflux. It is available in liquid and capsule form.

What are the Uses of Omeprazole?

Omeprazole is used to treat conditions like:

  1. Gastroesophageal reflux disease (GERD) - The acid in the stomach flows (reflux) back in the esophagus (tube connecting the mouth and stomach), usually causing a tear and sometimes ulcers in the food pipe (esophagus).

  2. Zollinger-Ellison syndrome - A rare condition where gastrin (a gut hormone) causes small tumors to form in the pancreas and/or duodenum (upper part of small intestine). These tumors produce large quantities of acids causing stomach, duodenal, and sometimes jejunal ulcers often together with symptoms of diarrhea.

  3. Barrett's esophagus- A condition in the esophagus due to prolonged reflux of acid content into the food pipe from the stomach. In this condition, Omeprazole is used for the prevention of cancerous changes in the lining of the food pipe.

  4. H.pylori infection - Bacterial infection caused by Helicobacter pylori.

  5. Gastric and duodenal ulcers - Omeprazole is used in NSAID induced ulcers, and in combination with antibiotics is used to treat gastric and duodenal ulcers caused by H.pylori.

  6. Heartburn - Burning pain in the chest due to acidity is called heartburn.

  7. Prevents upper gastrointestinal tract bleeding - Duodenal (beginning part of small bowel) ulcers, stomach ulcers, and erosive gastritis are a few leading causes of upper gastrointestinal bleeding.

What is its Mechanism of Action?

Omeprazole is a selective, competitive, and irreversible proton pump inhibitor drug. It works by suppressing the production of stomach acid. It inhibits the gastric parietal cells found in the lining of the stomach from producing acid. It starts working within 1 hour of oral administration and is highly effective in the next 4 hours. The duration of its action lasts usually for 24 to 48 hours but may last about 72 hours.

How Should Omeprazole Be Used?

Omeprazole is available as 10 mg, 20 mg, and 40 mg of delayed-release capsule and 2.5 mg or 10 mg of delayed-release granules (to be mixed with water). A liquid form is also available. It should be taken at least 30 minutes before a meal, preferably before breakfast. It is either taken ones or twice a day depending on your condition and doctor’s prescription. Follow your doctor’s instructions or read the package label carefully before taking this medicine.

If you are taking the delayed-release capsule, swallow the capsule as a whole with water. Do not chew, crush, or break the capsule. If you are using the granules, then mix the 2.5 mg sachet with 5 ml water or 10 mg sachet with 15 ml of water and drink.

It takes 1 to 4 days for the drug to produce an optimum effect, so it is not used for immediate relief. Do not take it for more than 4 months continuously without consulting your doctor. It is not advisable to stop or start taking Omeprazole without medical supervision.

What is the Dosage of Omeprazole?

The dosage differs for different patients and conditions. Always take medicines under medical supervision, it is never a good idea to self-medicate. The drug might have interactions that you might not be aware of.

The average adult doses of Omeprazole (oral suspension) are:

  • For peptic ulcer - 20 mg or 40 mg once or twice a day before a meal as per your doctor’s prescription.

  • For GERD - 20 mg once or twice a day as per your doctor’s prescription, before a meal for up to 8 weeks.

  • For Zollinger-Ellison syndrome - 60 mg once or twice a day as per your doctor’s prescription, before a meal.

What Are the Brand Names for Omeprazole?

A few of the common brand names are:

  • Prilosec.

  • Zegerid.

  • Omesec.

  • Losec.

What to Do If I Miss a Dose?

If you forget to take a dose, take it as soon as you remember. But if it is almost time for your next dose, then just skip the missed dose and continue with your normal schedule. Do not take two doses at a time.

How to Store and Dispose of This Medicine?

It should be stored at room temperature in a closed container. It should be kept away from heat, cold, and moisture. Dispose of outdated or expired medicines. Do not flush this medicine. It is best you dispose of expired medicine through medicine take-back program. Keep all medicines away from children.

What are the Side Effects of Omeprazole?

The common side effects are:

  • Headache.

  • Constipation or diarrhea.

  • Vomiting.

  • Nausea.

  • Stomach pain.

  • Gas.

The serious side effects include:

  • Hives.

  • Itching.

  • Difficulty breathing.

  • Swelling of the face, throat, ankles, etc.

  • Irregular heartbeat.

  • Muscle weakness.

  • Blood in urine and decreased urine.

  • Yellow discoloration of the skin.

  • Joint pain.

  • Dizziness.

  • Fatigue.

  • Allergy.

If you notice any of these side effects, get medical attention immediately.

What Are the Drug Interactions?

Some medicines might interact with Omeprazole and might cause side effects. Tell your doctor if you are taking the following medicines:

  • Digoxin.

  • Cilostazol.

  • Antifungals like Itraconazole, Ketoconazole, and Posaconazole.

  • Methotrexate.

  • Phenytoin.

  • Rifampin.

  • Antiplatelets like Clopidogrel and Warfarin.

  • HIV medications.

Precautions of Omeprazole

  • Always take any medicines including herbal and other supplements after consulting your doctor. If your doctor has prescribed you Omeprazole, then inform him or her if you are taking any of the above drugs.

  • Do not take this if you are allergic to it, as it causes severe allergic reactions.

  • Taking Omeprazole for more than 4 months might inhibit vitamin B12 absorption and cause vitamin B12 deficiency.

  • This medicine increases the chances of hip, wrist, and spine fracture for older patients due to a decrease in the absorption of calcium.

  • May cause drug-induced lupus.

  • Taking this medicine for more than a year might cause low magnesium in the blood.

  • Long term treatment of this medicine may cause iron deficiency due to impaired absorption.

  • Long term treatment with Omeprazole increases the risk of Clostridium Difficile infection of the colon and other gut infections.

  • In patients with decompensated cirrhosis, prolonged therapy increases the risk of spontaneous bacterial peritonitis.

  • Long term use might also increase the risk for fundal gland polyp, which is a noncancerous (benign) tissue growth in the upper part of the stomach.

  • Patients with liver diseases should inform your doctor before taking this medicine.

What are the Symptoms of Overdose?

Consuming more than the recommended dosage of Omeprazole might cause the following symptoms:

  • Drowsiness.

  • Confusion.

  • Blurred vision.

  • Dryness of mouth.

  • Headache.

  • Flushing.

  • Increased sweating.

  • Nausea.

  • Irregular heartbeat.

Get immediate medical attention if you develop any overdose symptom.

Frequently Asked Questions


Does Omeprazole Cause Any Harmful Effects?

Short-term use of Omeprazole is not associated with any serious adverse effects. However, long-term use (one year or more) may result in increased infection, deficiency of Vitamin B12, mouth ulcers, and in some individuals, bone fractures. Always talk to the doctor regarding the directions, time, and frequency of drug use.


When Is the Best Time to Take Omeprazole?

Omeprazole is generally prescribed to be taken once daily in the morning. The medication aids in acid reflux and heartburn. Hence, it is preferable to be taken 45 minutes to one hour before a meal. If Omeprazole is prescribed twice daily in case of GERD (gastroesophageal reflux disease), the tablets should be taken once in the morning and once in the evening.


Can I Take Omeprazole Every Day?

Omeprazole can be taken for symptomatic relief from heartburn or acid reflux. The duration of the therapy should, however, be as per the advice of the physician. Different people respond differently to medications. Hence, prolonged use should only be done after talking to the doctor.


Can Omeprazole Cause Weight Gain?

Long-term use of Omeprazole has been reported to increase weight in people administering Omeprazole. However, it is not known if the cause of weight gain is due to the medication. It is thought to be linked to increased food intake due to better symptom control in these patients.


How Long Does Omeprazole Take to Work?

Omeprazole reduces gastric secretion within one hour of the drug administration. A considerable reduction in the symptoms may be experienced within two to four days following the start of the therapy. Complete action may be observed within three to four weeks after starting the drug in case of GERD.


How to Discontinue Omeprazole Use?

In the case of long-term use of Omeprazole tablets, discontinuation of the drug is not done abruptly. The doctor will rather taper the dose slowly and then stop the drug altogether.


Does Omeprazole Cause Anxiety?

Recent reports have indicated that the medication is said to cause anxiety and cognitive impairments more likely, especially in elderly patients. Patients on therapy for depression also report hallucinations, anxiety, uneasiness, and insomnia upon Omeprazole administration.


Does Omeprazole Increase Tiredness?

Omeprazole can reduce magnesium levels in the body. A decrease in magnesium levels can lead to symptoms like fatigue, tiredness, dizziness, etc. The general side effects of the drug include drowsiness and increased sleepiness.


Can I Eat Right After Taking Omeprazole?

Omeprazole must be taken 45 minutes to 1 hour before a meal. Taking food immediately after administering the tablet may decrease the efficacy of the medication. Follow the instructions carefully for optimal control of stomach acidity.
Dr. Ambalathu Veettil Hussain Shihaz
Dr. Ambalathu Veettil Hussain Shihaz

Medical Gastroenterology


proton-pump inhibitorsomeprazoleheartburnacid reflux
Community Banner Mobile
By subscribing, I agree to iCliniq's Terms & Privacy Policy.

Source Article ArrowMost popular articles

Ask your health query to a doctor online

Medical Gastroenterology

*guaranteed answer within 4 hours

Disclaimer: No content published on this website is intended to be a substitute for professional medical diagnosis, advice or treatment by a trained physician. Seek advice from your physician or other qualified healthcare providers with questions you may have regarding your symptoms and medical condition for a complete medical diagnosis. Do not delay or disregard seeking professional medical advice because of something you have read on this website. Read our Editorial Process to know how we create content for health articles and queries.

This website uses cookies to ensure you get the best experience on our website. iCliniq privacy policy