Digestive health · Proton pump inhibitor (PPI)
Omeprazole
Omeprazole is a proton pump inhibitor that reduces stomach acid production. Used for reflux, heartburn, and ulcer conditions.
OTCPregnancy: cautionKidney warningLiver warningAlcohol interactionPaediatric useSenior precautionOverview & typical uses
Omeprazole is a proton pump inhibitor that reduces stomach acid production. Used for reflux, heartburn, and ulcer conditions.
Primary uses
- Frequent heartburn and acid reflux
- Stomach and duodenal ulcer treatment (under medical supervision)
- H. pylori infection eradication regimens (as part of combination therapy)
How it works
Irreversibly blocks the proton pumps in stomach lining cells, sharply reducing acid production.
Available forms & strengths
- Capsule — 10 mg, 20 mg, 40 mg (Oral)
- Tablet (delayed release) — 20 mg (Oral)
General precautions & contraindications
Do not use if
- Known allergy to omeprazole or other PPIs
- Concurrent use with rilpivirine (HIV medicine)
Pregnancy
Use with caution — discuss with clinician. Reassuring data at usual amounts; discuss with a clinician for regular use.
Breastfeeding
Use with caution — discuss with clinician. Small amounts pass into milk; usually considered acceptable.
Kidney considerations
- No routine adjustment needed for typical use.
Liver considerations
- Discuss with a clinician in severe liver disease.
Paediatric use
Under clinical supervision.
Older adults
Long-term high-dose use may slightly increase risk of fractures, B12 deficiency, or C. difficile — periodic review recommended.
Common side effects
- Headache
- Diarrhoea or constipation
- Abdominal pain
- Nausea
Serious warnings — seek help if these appear
- Serious allergic reaction
- Low magnesium (with prolonged use)
- Bone fractures (long-term high-dose use)
- Vitamin B12 deficiency (long-term use)
Drug interactions
PPIs reduce absorption — avoid combination.
May reduce clopidogrel's blood-thinning effect — discuss alternatives with a clinician.
May slightly enhance anticoagulant effect — monitor INR when starting or stopping.
May raise methotrexate levels at high doses.
Food & alcohol precautions
Take before a meal (usually breakfast) for best effect.
Alcohol
- No major interaction, but alcohol can worsen reflux symptoms.
Storage, missed dose & overdose
Storage
Store below 25 °C, out of reach of children.
If a dose is missed
Take when remembered unless the next dose is near — do not double up.
Overdose
Overdose can cause drowsiness, headache, sweating. Seek medical advice for large overdoses.
What to monitor
- Long-term users benefit from periodic clinical review to check whether continued use is needed.
Frequently asked questions
Usually 30 to 60 minutes before breakfast for best effect.
Symptom relief may take a few days; full acid suppression develops over about a week.
Medical references
- British National Formulary — Omeprazole — BNF (NICE)
- FDA drug information — Omeprazole — U.S. Food & Drug Administration
Content last reviewed: 2025-01-01
Medical disclaimer
This information is for educational purposes only and should not replace professional medical advice. Please consult a licensed pharmacist or clinician for advice tailored to your personal circumstances.