Medication Information Leaflet

​What is this medication for?

Omeprazole is used to treat various conditions of the gastrointestinal (stomach and intestines) tract including: 
  • Gastro-oesophageal reflux disease (a condition where the acid from the stomach goes back up the food tube and throat, causing pain and a burning sensation known as heartburn)
  • Ulcers of the gastrointestinal tract (treatment and prevention)    

How should I take/use this medication?

  • Do not stop taking your medication without checking with your healthcare professional.
  • Take this medication 30 to 60 minutes before a meal. Capsules should be swallowed whole with water.
  • Contents of the capsule should not be chewed or crushed. 
  • If you have swallowing difficulties, the capsule can be opened and the contents swallowed or suspended in a slightly acidic fluid e.g. fruit juice. The suspension should then be taken within 30 minutes. Alternatively you can open the capsule and swallow the contents.
  • A liquid preparation is available in some hospitals.

What should I do if I forget to take/use this medication?

If you forget to take a dose, take it as soon as you remember. Then take your next dose at the usual time. Do not take two doses to make up for the missed dose.

What precautions should I take?

Inform your healthcare professional if: 
  • You are allergic to this medication or any of the other ingredients of this medication
  • You are pregnant, planning to become pregnant, or breastfeeding 
  • You are taking any other medications, including supplements, traditional medications and herbal remedies. 
  • If symptoms (including abdominal pain) persist despite taking this medicine or you develop bloody stool (including blackened stool) or vomit.
  • This medication may hide the symptoms of other diseases. Inform your healthcare professional if you experience weight loss for no reason or are vomiting food or blood.
  • This medication may cause the level of magnesium in your body to decrease if you use it for long duration. Inform your healthcare professional if you experience muscle cramps, dizziness or shaking.
  • This medication may increase your risk of diarrhoea caused by a type of bacteria called Clostridium difficile. Inform your healthcare professional if you have watery or bloody stools that do not stop after a few days.
  • This medication may increase your risk of bone fractures if you have osteoporosis, a condition where your bones become weak or fragile.

What are some side-effects that I need to seek medical advice immediately?

The symptoms of a drug allergy include one or more of the following:
  • Swollen face/eyes/lips/tongue
  • Difficulty in breathing
  • Itchy skin rashes over your whole body.
Furthermore, unusual symptoms such as muscle spasms (tetany), palpitations, dizziness and seizures may be a sign of low magnesium in the body.

If you experience any of these symptoms, you should stop your medicine and see your healthcare professional immediately.

What are some other side-effects of this medication?

Side effects of omeprazole include headaches, gastrointestinal side effects (e.g. abdominal pain, diarrhoea, nausea and vomiting and wind).
  • If persistent please consult your healthcare professional.

What food or medication should I avoid when I take this medication?

Inform your healthcare professional if you are taking or intend to take any other medication, supplements, traditional medications or herbal remedies. 

This includes: 
  • Medicines which may be used to treat human immunodeficiency virus (HIV) infection
  • Certain blood thinners (e.g. warfarin, clopidogrel).
  • Certain anti-fungal medicines (e.g. ketoconazole).
  • Certain drugs to treat mood (e.g. citalopram, imipramine and clomipramine).
  • Certain drugs to treat seizures (e.g. phenytoin) .
  • Other medicines such as digoxin, cyclosporin, methotrexate and iron salts.

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children. 

How should I throw away this medication safely?

Pack this medication into a black trash bag and seal it tightly before throwing into the rubbish chute or bin. 

Please take note that the above is not a complete list of all possible side effects. If you have any concerns about your medication or if you have other side effects that you think are caused by this medication, please consult your doctor or pharmacist.

If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

Last updated on September 2022

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