Fast home delivery
Professional and knowledgeable


  • Used to treat stomach ulcers and heartburn caused by acid reflux
  • Also used as a stomach coater to prevent stomach problems
  • Reduces the production of stomach acid
  • Capsules for oral use
  • Also suitable for use in children

About Omeprazole

Omeprazole is a stomach medicine. It contains the active substance omeprazole, which belongs to a group of medicines called proton pump inhibitors. They work by reducing the amount of acid that your stomach produces. This helps alleviate symptoms such as heartburn and stomach pain.

Omeprazole is prescribed to treat the following conditions:

In adults:

  • Gastro-oesophageal reflux disease (GORD). This is where acid from the stomach escapes into the gullet (the tube which connects your throat to your stomach) causing pain, inflammation and heartburn.
  • Ulcers in the upper part of the intestine (duodenal ulcer) or stomach (gastric ulcer).
  • Ulcers which are infected with bacteria called Helicobacter pylori. If you have this condition, your doctor may also prescribe antibiotics to treat the infection.
  • Ulcers caused by medicines called NSAIDs (Non-Steroidal Anti-Inflammatory Drugs). Omeprazole can also be used to stop ulcers from forming if you are taking NSAIDs.
  • Too much acid in the stomach caused by a growth in the pancreas (Zollinger-Ellison syndrome).

In children over one year of age and weighing 10 kg or more:

  • Gastro-oesophageal reflux disease (GORD).
  • Ulcers which are infected with bacteria called Helicobacter pylori. If your child has this condition, your doctor may also prescribe antibiotics to treat the infection.

How to use Omeprazole

Omeprazole is available in capsule form. It is recommended that you take this medicine in the morning. You can take your capsules with food or on an empty stomach. Swallow the capsule whole with plenty of liquid. Do not chew or crush the capsules. This is because they contain coated pellets which stop the medicine from being broken down by the acid in your stomach. It is important not to damage the pellets. If you have difficulty swallowing, you can also break the capsules and disperse them in a spoonful of liquid according to the instructions in the package leaflet.


Dosage varies per person and is determined by a doctor for each specific patient depending on the symptoms. In children, the dosage is determined based on body weight. The recommended dose in adults is:

  • For most conditions: 10 to 20 mg once daily.

The doctor will tell you how long you need to use this medicine. See the package leaflet for more information.


This medicine does not interact with alcohol or impair your ability to drive safely.

If you use more/forget to use Omeprazole

If you take more Omeprazole capsules than you were told to, consult your doctor or pharmacist.

If you forget to take a dose of Omeprazole, you may take it as soon as you remember, unless it is almost time for your next scheduled dose. Do not take a double dose to make up for the forgotten one.

When not to use Omeprazole

Omeprazole is not suitable for everyone. Do not use this medicine if:

  • You are allergic to omeprazole, medicines containing other proton pump inhibitors (e.g., pantoprazole, lansoprazole or rabeprazole) or any of the other ingredients in this medicine (see section 'What Omeprazole contains').
  • You are taking any medicine containing nelfinavir (for HIV infection).

When should this medicine be used with caution?

If any of the following happen to you before you start taking Omeprazole or while you are taking it, talk to your doctor straight away:

  • You lose a lot of weight for no reason and have problems swallowing.
  • You get stomach pain or indigestion.
  • You begin to vomit food regularly or if you notice your vomit contains blood.
  • You pass black stools (blood-stained faeces).
  • You experience severe or persistent diarrhoea, as omeprazole has been associated with a small increase in infectious diarrhoea.
  • You have severe liver problems.

Be sure to consult a doctor if these symptoms occur during treatment with Omeprazole.

Pregnancy and breastfeeding

Inform your doctor if you are pregnant or breastfeeding before using this medicine. Your doctor will decide whether or not you should be given this medicine.

Other medicines and Omeprazole

Tell your doctor if you are taking, have recently taken or might take any other medicines. This includes medicines obtained without a prescription and herbal medicines.

Do not take Omeprazole if you are taking a medicine containing nelfinavir (used to treat HIV).

Tell your doctor or pharmacist if you are taking any of the following medicines:

  • Ketoconazole, itraconazole or voriconazole (used to treat infections caused by a fungus).
  • Digoxin (used to treat heart problems).
  • Diazepam (used to treat anxiety, relax muscles or in epilepsy).
  • Phenytoin (used in epilepsy).
  • Medicines that are used to thin your blood, such as warfarin or other vitamin K blockers.
  • Rifampicin (used to treat tuberculosis).
  • Atazanavir and saquinavir (used to treat HIV infections).
  • Tacrolimus (in cases of organ transplantation).
  • St John’s wort (Hypericum perforatum) (used to treat mild depression).
  • Cilostazol (used to treat intermittent claudication).
  • Clopidogrel (used to prevent blood clots).

Your doctor will know whether these medicines can be taken alongside Omeprazole.

Side effects

Like all medicines, this medicine can cause side effects, although some people may not experience any. Side effects that are known to be associated with Omeprazole include:

Common (may affect up to 10 in 100 people):

  • Headache.
  • Stomach or intestinal problems.

Uncommon (may affect up to 10 in 1,000 people):

  • Swelling of the feet and ankles.
  • Disturbed sleep (insomnia).
  • Dizziness, tingling feelings such as 'pins and needles', feeling sleepy.
  • Spinning feeling (vertigo).
  • Changes in blood tests that check how the liver is working.
  • Skin rash, lumpy rash (hives) and itchy skin.
  • Generally feeling unwell and lacking energy.

Rare (may affect up to 10 in 10,000 people):

  • Blood count problems, e.g., reduced numbers of white blood cells or blood palates. This may cause weakness, bruising or more infections.
  • Allergic reactions, sometimes very severe, including swelling of the lips, tongue and throat, fever, and wheezing.
  • Low levels of sodium in the blood. This may cause weakness, being sick (vomiting) and cramps.
  • Feeling agitated, confused or depressed.
  • Taste changes.
  • Eyesight problems, such as blurred vision.
  • Suddenly feeling wheezy or short of breath (bronchospasm).
  • Dry mouth.
  • An inflammation of the inside of the mouth.
  • An infection called thrush which can affect the gut and is caused by a fungus.
  • Liver problems, including jaundice, which can cause yellow skin, dark urine and tiredness.
  • Hair loss (alopecia).
  • Skin rash on exposure to sunshine.

For a complete list of side effects, see the package leaflet. If the side effects are severe or if you get any side effects that are not listed in the package leaflet, contact your doctor or pharmacist.

If you notice any of the following rare but serious side effects, stop taking this medicine and contact a doctor or go to the nearest hospital casualty department immediately:

  • Sudden wheezing, swelling of your lips, tongue and throat or body, rash, fainting or difficulties in swallowing and breathing (severe allergic reaction).
  • Reddening of the skin with blisters or peeling. There may also be severe blisters and bleeding in the lips, eyes, mouth, nose and genitals. This could be StevensJohnson syndrome or toxic epidermal necrolysis.
  • Liver problems. Symptoms can include jaundice which can cause yellow skin, dark urine, and tiredness.

What Omeprazole contains

The active substance is omeprazole. Each gastro-resistant hard capsule contains 10 mg, 20 mg or 40 mg omeprazole.

Package leaflet

Read the package leaflet before use. The official package leaflet of Omeprazole is available for download here.

Patient Leaflet(s)

Reviewed by:

Dr Arco Verhoog, Pharmacist Registrationnumber: BIG: 19065378617 Last checked: 17-08-2023 | Still valid

Affiliated doctors

You know perfectly well what's good and what isn't good for you. Nevertheless, making the right choice can be difficult. We are Dokteronline. We believe in self-management when it comes to your health.

Dr. E. Tanase

MD General practitioner / emergency medicine

Dr. P. Mester

MD General practitioner / internal medicine

Dr. I. Malik

MD General practitioner / general medicine
Back to top