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Omeprazole Capsules
From: £7.99
Or £7.19 / month
Omeprazole is one of the UK’s most widely acid-suppressing medicines. As a proton pump inhibitor (PPI), it blocks acid production at its source rather than simply neutralising existing acid. Taken once daily before food, it provides sustained relief for GORD, frequent heartburn, oesophagitis, gastric ulcers, and prevention of NSAID-related ulcers. Full effect builds over 2–4 days of consistent use.
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Additional information
| Strength | 10mg, 20mg |
|---|---|
| Quantity | 28, 56 |
Overview
Content Written by:
Hanifa Tai
Hanifa Tai
Role: Pharmacist & Content Writer
GPhC Number: 2074961
Content Published: 01/04/2026
Next Review: 01/04/2027
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Description
What Is Omeprazole?
Omeprazole belongs to a group of medicines known as proton pump inhibitors (PPIs). It reduces the amount of acid produced by the stomach. Unlike antacids, which neutralise acid already present, Omeprazole works at the source by blocking acid production itself. This provides longer-lasting control and supports recovery in acid-related conditions. It is typically taken once daily before food.
What Conditions Does Omeprazole Treat?
Omeprazole is licensed in the UK for: Gastro-oesophageal Reflux Disease (GORD) — reduces acid exposure and supports healing; Chronic or frequent heartburn occurring two or more times per week; Gastric and duodenal ulcers — suppresses acid to allow healing; Prevention of NSAID-associated ulcers in patients taking anti-inflammatory medicines; Helicobacter pylori eradication — used alongside antibiotics; and Zollinger–Ellison Syndrome — rare condition requiring higher doses under specialist care.
How Does Omeprazole Work?
Specialised cells in the stomach lining produce acid via proton pumps. Omeprazole blocks these pumps, significantly reducing acid secretion. Acid production begins to fall within 1–2 hours of taking a dose, but maximum effect develops over several days of consistent use. Because it works progressively, Omeprazole is most effective when taken regularly rather than occasionally.
How to Take Omeprazole Capsules
Swallow capsules whole with water. Do not crush or chew. For reflux and heartburn, the usual adult dose is 20mg once daily, taken 30–60 minutes before food, ideally in the morning. Some individuals may require 40mg daily depending on severity. If you have twice daily, doses are typically taken before breakfast and before the evening meal. Taking it at the same time each day improves consistency.
Omeprazole vs Lansoprazole vs Famotidine
Omeprazole and Lansoprazole are both PPIs — they work the same way and are considered similarly effective. Some patients respond better to one than the other. Famotidine is an H2 blocker working by a different mechanism, providing faster onset (1–3 hours) but shorter duration. PPIs are generally preferred for confirmed GORD or oesophagitis. Famotidine may suit intermittent or on-demand symptoms. Your pharmacist will recommend the most appropriate option.
How Long Does Treatment Last?
Standard courses for reflux typically last 4 to 8 weeks. Shorter initial supplies (14–28 days) are often provided to assess response. If symptoms persist beyond 28 days, recur quickly, or worsen, further medical evaluation is needed. Longer-term therapy may be appropriate but requires clinical review.
FAQ
Q: How quickly does Omeprazole work?
A: Omeprazole begins reducing acid production within 1–2 hours. Some people notice improvement within 24 hours. The full therapeutic effect builds over 2–4 days of consistent daily use. Take it every day rather than only when symptoms occur for best results.
Q: Can I take Omeprazole long-term?
A: Omeprazole can be used long-term where clinically appropriate, but periodic review is recommended to confirm ongoing need. Long-term high-dose use has been associated with low magnesium, reduced B12 absorption, and slightly increased fracture risk. Your pharmacist will aim for the lowest effective dose.
Q: Does Omeprazole interact with other medicines?
A: Yes. Important interactions include clopidogrel, warfarin, methotrexate, digoxin, phenytoin, diazepam, certain antifungals, HIV medications, and erlotinib. Always declare all your medications during the consultation.
Q: Is Omeprazole safe in pregnancy?
A: Omeprazole is generally considered one of the safer PPIs during pregnancy when clinically necessary. However, it should only be used following appropriate assessment. Declare pregnancy or breastfeeding during your consultation.
Q: What’s the difference between Omeprazole capsules and dispersible tablets?
A: Both contain the same active ingredient at the same dose and work identically. Dispersible tablets can be dissolved in water before swallowing — suitable for patients who find capsules difficult to swallow. Standard capsules are swallowed whole and are typically a lower-cost option.
Side Effects
Common Side Effects
Usually mild and temporary:
- Headache
- Nausea
- Diarrhoea
- Constipation
- Abdominal pain
- Flatulence (usually mild and temporary)
Rare but Serious — Seek Urgent Medical Attention
- Severe allergic reaction (swelling of face/throat, difficulty breathing) — seek urgent help
- Significant skin reactions (severe blistering rash) — seek urgent help
- Liver problems — seek urgent help
Do Not Take If You:
- You are allergic to Omeprazole or other PPIs
- You are taking HIV medications such as nelfinavir
- You have severe liver impairment
- You have unexplained weight loss or difficulty swallowing
- You have signs of gastrointestinal bleeding
Key Drug Interactions — Always Declare All Medicines:
- Clopidogrel
- Warfarin
- Methotrexate
- Digoxin
- Phenytoin
- Diazepam
- Certain antifungals
- HIV medications
- Erlotinib
Long-Term Safety Note: Prolonged PPI use may be associated with low magnesium levels, reduced vitamin B12 absorption, slightly increased fracture risk, and increased susceptibility to certain gut infections. These risks are generally small and more relevant with long-term high-dose use. Regular reviews help ensure continued need and safety.
Seek Urgent Medical Attention If You Develop: difficulty swallowing, vomiting blood, black or tarry stools, severe chest pain, or unexplained weight loss.
