For adults with acid reflux or gastro oesophageal reflux disease (GORD), omeprazole is commonly prescribed at 20mg once daily. The right dose depends on the condition being treated, how severe it is and how you respond to treatment. Some people may need a lower dose for maintenance, while 40mg or a divided dose may be used for certain conditions under medical supervision. NICE lists 20mg once daily as the standard dose for GORD, with 10mg once daily as a low or maintenance dose and higher doses used in specific circumstances.
Your prescriber decides the right dose and treatment length for you. This guide explains the usual UK dosing options, but it does not replace an individual medical assessment.
Key things to know
- 20mg once daily is the standard dose commonly used for adult GORD, while 10mg once daily may be used as a lower or maintenance dose.
- 40mg once daily may be used for severe oesophagitis and certain other conditions when a higher dose is appropriate.
- Omeprazole can be taken with or without food, so there is no strict requirement to take it 30 to 60 minutes before breakfast.
- Twice daily dosing is used in some situations, including certain H. pylori treatment regimens and some specialist treatment plans. It is not something to add yourself if your usual once daily dose is not controlling your symptoms.
- BNFc (British National Formulary for Children) provides prescribing information for children and adolescents. This guide focuses on adult dosing.
- GORD treatment is commonly given for 4 to 8 weeks initially, depending on the condition and response. Long term treatment should be reviewed periodically.
How Omeprazole Works
Omeprazole is a proton pump inhibitor (PPI). It reduces the amount of acid produced by the proton pumps in the lining of your stomach.
By reducing stomach acid, omeprazole can help relieve symptoms such as heartburn and acid reflux and can give irritated areas of the oesophagus time to heal when acid is contributing to the problem.
The effect is not the same as an instant antacid. Some people notice their symptoms improving within the first few days, while conditions such as reflux oesophagitis can take longer to heal. The time it takes to feel better varies between people and depends on the condition being treated.
Standard Adult Dosing
| Dose level | Strength | Typical use |
|---|---|---|
| Lower or maintenance | 10mg | Lower dose or maintenance treatment in appropriate patients |
| Standard | 20mg | Standard dose for typical GORD, once daily |
| Higher | 40mg | Severe oesophagitis and certain other conditions, when prescribed |
NICE lists omeprazole 20mg once daily as the full or standard dose for GORD and 10mg once daily as a low or on demand dose. For severe oesophagitis, NICE lists 40mg once daily as the full or standard dose.
The exact dose can be different for other conditions. For example, some gastric and duodenal ulcers may be treated with 20mg once daily, while 40mg once daily may be used when an ulcer has responded poorly to the standard dose.
Can Omeprazole Be Taken Twice a Day?
Yes, omeprazole can be prescribed twice a day in certain circumstances, but this is not the usual dosing schedule for uncomplicated acid reflux.
For example, some H. pylori eradication regimens use omeprazole 20mg twice daily alongside antibiotics for one week. The exact antibiotic combination depends on current treatment guidance and the individual patient.
Twice daily dosing can also be used in some people with conditions that need more intensive acid suppression. NICE lists twice daily dosing as a double dose for severe oesophagitis in its dosing information.
If your once daily dose is not controlling your symptoms, do not simply add a second dose. Your prescriber may consider changing the dose, switching to another PPI, investigating the symptoms further or using another treatment approach.
H. pylori Eradication: A Genuine Reason for Twice Daily Dosing
If tests confirm a Helicobacter pylori (H. pylori) infection, treatment usually combines a PPI such as omeprazole with antibiotics.
One licensed treatment regimen uses omeprazole 20mg twice daily alongside two antibiotics for one week. Other combinations are also possible, depending on factors such as antibiotic resistance and the treatment guidance being followed.
This is different from treating ordinary heartburn or uncomplicated GORD. If you are being treated for H. pylori, your prescriber will explain exactly which medicines to take, how often to take them and for how long.
Do You Need to Take Omeprazole Before Food?
No, not strictly. Current NHS guidance on omeprazole says that omeprazole can be taken with or without food.
There is no universal 30 to 60 minute rule that applies to every omeprazole product. The NHS advises taking a once daily dose at the same time each morning, or at the same time each morning and evening if it has been prescribed twice daily.
The most important thing is to follow the instructions supplied with your particular medicine. If your prescriber or pharmacist has given you different instructions, follow those.
What About BNFc Dosing?
The BNFc (British National Formulary for Children) provides prescribing information for children and adolescents. Children's doses can depend on factors such as age, body weight and the condition being treated.
This is different from the standard adult dosing information covered in this guide. EverydayMeds provides treatment for adults, so BNFc dosing should not be used to work out an adult dose or to decide how much omeprazole to take.
If you are looking for information about omeprazole for a child, speak to a GP, pharmacist or paediatric specialist rather than applying the adult doses shown here.
Common Side Effects
Common side effects of omeprazole can include headache, stomach pain, nausea, diarrhoea, constipation, vomiting and wind. Dizziness can also occur. Not everyone gets side effects, and they may improve as your body gets used to the medicine.
Serious side effects are uncommon, but severe diarrhoea, symptoms of a serious allergic reaction or other unusual symptoms should be assessed by a healthcare professional.
Low magnesium can occur with prolonged PPI treatment. Symptoms can include muscle cramps, muscle twitches, weakness or an irregular heartbeat. If you develop these symptoms while taking omeprazole, speak to your doctor.
Side effects cannot be predicted simply from the number of milligrams you take. If you develop problems after starting omeprazole, your pharmacist or prescriber can help decide whether the dose, treatment or medicine needs reviewing.
Long Term Use: Why Review Matters
Long term PPI treatment has been associated with problems such as low magnesium, vitamin B12 deficiency and an increased risk of fractures in some people. Rare fundic gland polyps have also been reported with prolonged treatment. These risks do not mean that everyone taking omeprazole will develop a problem, but they are reasons to review long term treatment when appropriate.
NICE recommends reviewing people who are taking long term PPI treatment to check whether continued treatment is needed and whether the dose can be reduced when appropriate.
If you have been taking omeprazole for a long time without a review, speak to your prescriber. A review does not mean that something is wrong. It is simply a chance to check that the medicine and dose are still right for you.
How to Take Omeprazole Correctly
Swallow gastro resistant capsules and tablets with water. Do not chew or crush capsules or tablets that are labelled gastro resistant or enteric coated, as this can affect the way the medicine is released.
If you have difficulty swallowing capsules or tablets, ask your pharmacist about other formulations. Some omeprazole tablets can be dissolved in water, and oral suspension is also available for some patients.
If you are taking other medicines, herbal remedies, vitamins or supplements, tell your pharmacist or prescriber. Omeprazole can interact with some medicines, including clopidogrel, warfarin, digoxin, phenytoin and St John's wort.
Treatment Duration
The length of treatment depends on the condition being treated.
For GORD, NICE recommends a full dose PPI for 4 or 8 weeks.
For reflux oesophagitis, the usual omeprazole dose is 20mg once daily, with treatment generally given for 4 to 8 weeks depending on the response and severity.
Some people need longer term maintenance treatment. If you need omeprazole for an extended period, your prescriber should review whether you still need it and whether the dose remains appropriate.
If Omeprazole Is Not Controlling Your Symptoms
If your current dose is not giving you enough relief, do not automatically increase it yourself.
Your prescriber may check whether you are taking the medicine correctly, whether the treatment has been given enough time to work, whether another PPI would be more suitable, or whether your symptoms need further investigation.
Other medicines used for acid related conditions include lansoprazole, pantoprazole, esomeprazole and famotidine. The best option depends on your symptoms, medical history and other medicines you take.
Speak to a healthcare professional before changing treatment, particularly if your symptoms are persistent, worsening or different from your usual reflux symptoms.
Missed and Extra Doses
If you miss a dose, take it as soon as you remember unless it is nearly time for your next dose. If it is nearly time, skip the missed dose and take your next dose at the usual time. Do not take two doses at the same time to make up for a missed dose.
If you accidentally take an extra dose, it is unlikely to cause problems in most cases. However, the NHS advises getting medical advice if you have taken more than the amount stated on your packet, leaflet or prescription. You can contact NHS 111 or speak to a pharmacist for advice.
These instructions apply whether you are taking 10mg, 20mg or 40mg, although your individual prescription may contain different instructions.
Available Treatments
| Treatment | Price |
|---|---|
| Lansoprazole 15mg Capsules | From £5.99 |
| Pantoprazole | From £5.99 |
| Famotidine Tablets | From £8.49 |
| Lansoprazole 15mg Orodispersible Tablets | From £8.49 |
| Esomeprazole | From £16.99 |
| Omeprazole 20mg | From £12.99 |
| Rabeprazole | From £19.99 |
| Losec MUPS 20mg Tablets | From £29.99 |
Medical Disclaimer
This page provides general information about omeprazole dosing for acid reflux. It is not a substitute for personalised medical advice.
Do not change your dose, start taking omeprazole twice daily or continue treatment for longer than advised without speaking to your prescriber or pharmacist first.
If your symptoms are not improving, keep coming back or are getting worse, speak to a healthcare professional. Persistent symptoms may need further assessment rather than simply a higher dose.
