Omeprazole – Proton pump inhibitor for acid reflux and stomach protection.
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What is Omeprazole?
Omeprazole is a proton pump inhibitor that effectively reduces stomach acid production. It’s widely used to treat acid reflux, heal stomach ulcers, and protect the stomach from damage caused by other medications or bacterial infections.
Book an online consultation if you’re experiencing persistent heartburn, acid reflux, or stomach pain that may be related to excess stomach acid. Our GPs can assess your symptoms and determine if Omeprazole is the right treatment for your digestive health needs.
What is Omeprazole used for?
- Gastro-oesophageal reflux disease (GORD)
- Stomach and duodenal ulcers
- Helicobacter pylori eradication (with antibiotics)
- Prevention of NSAID-induced ulcers
- Zollinger-Ellison syndrome
- Severe heartburn and acid indigestion
How does Omeprazole work?
A proton pump inhibitor that blocks the final step of stomach acid production by inhibiting the hydrogen-potassium pump in stomach cells, significantly reducing acid levels.
Dosage and Administration
Adults
20-40 mg once daily, usually taken in the morning before food. Can be increased to 80 mg daily if needed.
Children
Weight-based dosing required—specialist supervision usually needed.
Important Notes
- Take 30-60 minutes before food for best effect.
- Swallow capsules whole—do not chew or crush.
- If you can't swallow capsules, contents can be mixed with water or fruit juice.
- May take 1-4 days to reach full effect.
Side Effects
Common Side Effects
- Headache
- Nausea and vomiting
- Diarrhoea or constipation
- Abdominal pain
- Flatulence (wind)
- Dizziness
Serious Side Effects
Seek immediate medical attention if you experience:
- Severe diarrhoea (C. difficile infection)
- Bone fractures (with long-term use)
- Low magnesium levels
- Vitamin B12 deficiency
- Kidney problems
- Severe allergic reactions
Important Warnings
- Long-term use may increase risk of bone fractures—calcium and vitamin D may be recommended.
- May mask symptoms of stomach cancer—persistent symptoms need investigation.
- Can reduce absorption of vitamin B12, iron, and magnesium with prolonged use.
- Tell your GP if you have liver problems—dose reduction may be needed.
- May interact with many other medications.
Drug Interactions
Tell your GP if you're taking any of the following medications:
- Warfarin—may increase bleeding risk.
- Clopidogrel—may reduce effectiveness of clopidogrel.
- Digoxin—may increase digoxin levels.
- Phenytoin—may increase phenytoin levels.
- Ketoconazole and some antifungals—reduced absorption.
- HIV medications—may affect absorption.
Frequently Asked Questions
How long does Omeprazole take to work?
You may notice some improvement within 1-2 days, but full effect usually takes 1-4 days. For healing ulcers, it may take several weeks.
Can I take Omeprazole long-term?
It can be used long-term under medical supervision, but your GP will regularly review the need and may recommend periodic breaks or monitoring.
Why must I take it before food?
Omeprazole works best when taken before eating because this is when the acid-producing pumps in your stomach are most active.
What happens if I stop taking Omeprazole suddenly?
You may experience 'rebound acid production' where symptoms temporarily worsen. Your GP may recommend gradually reducing the dose.
Medically Reviewed by: Mohammed Hassan - Independent Prescriber
Last Updated: 2025-01-14