Omeprazole at a glance
Medicine class
Proton pump inhibitor (PPI).
Main effect
Reduces stomach acid production.
Available forms
Selected UK products include gastro-resistant tablets or capsules, powder for oral suspension and oral solution.
Not instant relief
Reflux symptoms may take a few days to improve.
What is Omeprazole used for?
Licensed uses vary by formulation and age and include:
Reflux symptoms such as heartburn and acid regurgitation in adults.
Gastro-oesophageal reflux disease, including reflux oesophagitis, and maintenance after healing.
Treatment and prevention of gastric or duodenal ulcers, including NSAID-associated ulcers.
Use with appropriate antibiotics to eradicate Helicobacter pylori in peptic ulcer disease.
Zollinger–Ellison syndrome.
Reflux disease in children within the ages specified for the product.
How does Omeprazole work?
Omeprazole becomes active in the stomach’s acid-producing cells. It blocks the proton pump involved in the final step of acid secretion, reducing both resting and meal-stimulated acid production.
Omeprazole preparations and strengths
Capsule
Route: Oral
Strengths: 10 mg, 20 mg, 40 mg
Gastro-resistant capsule
Route: Oral
Strengths: 10 mg, 20 mg, 40 mg
How to take Omeprazole
Follow the instructions for the exact product supplied because administration differs between formulations.
Swallow gastro-resistant tablets whole; do not crush or chew them.
Capsules should usually be swallowed whole. Some specified products may be opened and the intact pellets mixed with a suitable slightly acidic soft food or drink; do not chew the pellets.
Shake oral suspension before measuring it with the supplied oral syringe. The selected powder-for-suspension product should normally be prepared by a pharmacist or healthcare professional and taken on an empty stomach.
Check the selected oral solution’s leaflet before opening or mixing it because instructions are product-specific.
Omeprazole side effects
Common or expected effects
- Headache
- Abdominal pain
- Constipation or diarrhoea
- Wind
- Nausea or vomiting
Get urgent medical advice
- Severe allergic reaction, including facial or throat swelling and breathing difficulty
- Blistering, peeling or widespread rash
- Severe or persistent diarrhoea
- Yellow skin or eyes, dark urine or other signs of liver injury
- Reduced urine output, blood in the urine or flank pain
- Marked weakness, confusion, muscle twitching, seizures or an irregular heartbeat
Omeprazole in pregnancy
Omeprazole can be used during pregnancy when clinically appropriate. UK pregnancy information identifies it as the preferred PPI when one is needed because it has the most pregnancy safety information. A prescriber or pharmacist should confirm treatment is appropriate, particularly for self-purchased products or unexplained symptoms.
Omeprazole while breastfeeding
Omeprazole is a preferred PPI during breastfeeding. Only very small amounts are expected in milk, and any swallowed by the infant is likely to be broken down in the gut. This applies most directly to healthy, full-term infants; seek specialist advice if the infant is premature or unwell.
Omeprazole interactions
Important examples are listed below; this is not exhaustive. Ask a pharmacist or prescriber to check all medicines, including non-prescription and herbal products.
Nelfinavir
Must not be used with omeprazole because omeprazole substantially reduces nelfinavir exposure.
Atazanavir
Omeprazole can reduce atazanavir exposure. The combination is generally not recommended and requires specialist management if unavoidable.
Clopidogrel
Omeprazole can reduce formation of clopidogrel’s active metabolite; concomitant use is discouraged unless considered essential.
Common questions about Omeprazole
Answers are fully visible for fast scanning and source review.
Can omeprazole be taken with food?
It depends on the formulation. Selected gastro-resistant tablets and capsules may be taken with or without food, while the selected powder-for-suspension product should be taken on an empty stomach. Follow the exact product’s leaflet.
Can omeprazole capsules be opened?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.