Starting a new medicine can feel like a lot to take in, so here is the straightforward version. For adults, omeprazole is commonly prescribed at 20mg once daily for gastro oesophageal reflux disease (GORD), symptomatic acid reflux and some related conditions. The right dose depends on the condition being treated and your individual circumstances.
Omeprazole can be taken with or without food. Some product information recommends taking it in the morning, while NHS guidance advises taking it at the same time each morning if you take it once a day.
Some people notice an improvement within the first few days, but this varies. The full effect of acid suppression develops over several days rather than providing the immediate relief you might expect from an antacid.
For adults in the UK who are starting omeprazole, this guide explains the usual doses, when and how to take it, what you may notice during the first few days and weeks, possible side effects, lifestyle measures that may help, and when your treatment may need reviewing.
Your prescriber will confirm the dose that is appropriate for you. This guide is intended to help you understand your treatment and does not replace personalised medical advice.
Key things to know
- 20mg once daily is a common adult dose for symptomatic GORD, but the appropriate dose depends on the condition being treated.
- Omeprazole can be taken with or without food. There is no general requirement to take it 30 to 60 minutes before breakfast.
- Some people notice an improvement within a few days, but the time needed for symptoms to settle varies from person to person.
- Swallow gastro resistant capsules whole with water. Do not chew or crush them. If you have difficulty swallowing, check the instructions for your particular product or ask a pharmacist, as some omeprazole capsules can be opened and the pellets taken with a suitable liquid or soft food.
- It is normal not to feel a dramatic difference on day one. This does not necessarily mean that the medicine is not working.
How Omeprazole Actually Works for gastro oesophageal reflux disease
Omeprazole is a proton pump inhibitor (PPI). It blocks the H+/K+ ATPase proton pump in the cells lining your stomach, reducing the amount of acid your stomach produces.
This is different from how an antacid works. An antacid neutralises acid that is already in the stomach, while omeprazole reduces the production of new stomach acid. Because of this difference, omeprazole does not usually give the same type of immediate relief as an antacid.
This can be useful to understand when you are taking omeprazole for the first time. If you do not feel a dramatic change immediately, that does not necessarily mean the medicine is not working. Its effect develops over time, with maximum acid suppression reached after several days of regular treatment.
Your Starting Dose
For adults with symptomatic gastro oesophageal reflux disease (GORD), the recommended omeprazole dose is 20mg once daily. Some people may respond adequately to 10mg daily, while higher doses may be prescribed for certain conditions or more severe disease.
If you have been prescribed 10mg, this can be appropriate in some circumstances, including lower dose treatment or long term management after reflux oesophagitis has healed. If you have been prescribed 40mg from the outset, this may reflect the condition being treated or its severity. Your prescriber will decide whether that dose is appropriate for you.
Older adults do not routinely need a lower omeprazole dose simply because of their age. Your prescriber may still take other health conditions and medicines into account when choosing your dose.
When Should You Take It?
There is no general requirement to take omeprazole strictly before food. NHS guidance says it can be taken with or without food. If you take it once a day, NHS guidance recommends taking it at the same time each morning.
This means you do not need to worry about getting the timing exactly 30 to 60 minutes before breakfast. The more useful habit is to take your medicine consistently and follow the instructions for your particular product.
Some product information recommends taking omeprazole in the morning, so follow the instructions supplied with your medicine and any advice from your prescriber or pharmacist.
Pick a time that is easy for you to remember. For many people, taking it as part of their morning routine makes it easier to remember the daily dose.
What to Expect: Your First Few Weeks
| Timeframe | What may be happening |
|---|---|
| First few days | Omeprazole starts reducing stomach acid. Some people begin to notice their symptoms improving, but you may not feel a major difference straight away. |
| Around day 4 | The acid reducing effect can become more established with regular daily treatment. Product information states that maximum acid suppression is reached within about 4 days. |
| Week 1 to 2 | You may have a clearer idea of how your symptoms are responding, although this varies between people. Continue taking the medicine as prescribed rather than changing the dose based on how you feel on a particular day. |
| Week 4 | If you are taking omeprazole for symptomatic GORD and your symptoms have not been controlled after 4 weeks, further assessment may be needed. |
This is a general guide, not a promise about how quickly your symptoms will improve. Some people respond sooner, while others may need further assessment or a different treatment approach.
NICE recommends a full dose PPI for 4 or 8 weeks for GORD, depending on the clinical situation. If your symptoms are not improving, are getting worse or continue despite treatment, speak to your prescriber or pharmacist rather than increasing the dose yourself.
Lifestyle Habits That Help Alongside Your First Course
Alongside taking omeprazole as prescribed, a few simple changes may help manage reflux symptoms. These include avoiding large meals close to bedtime, cutting back on foods and drinks that you know trigger your symptoms, reducing alcohol if it makes your symptoms worse, and raising the head of your bed if you have night time reflux.
NICE also recommends avoiding known triggers where possible. These can include coffee, chocolate, fatty foods and alcohol, although triggers vary from person to person. Having your main meal well before going to bed may also help.
These measures do not replace prescribed treatment, but they may help alongside it.
Looking Beyond the First Few Weeks
If you need omeprazole for longer term treatment, your prescriber may review whether you still need it and whether the dose remains appropriate.
NICE recommends using the lowest dose needed to control symptoms where appropriate. For people who need long term management of dyspepsia, NICE recommends an annual review and encourages stepping down or stopping treatment where this is appropriate. People with conditions that require ongoing treatment may need to continue their PPI for longer.
Long term PPI treatment has also been associated with problems such as vitamin B12 deficiency, low magnesium and fractures in some people. These risks depend on factors such as the length of treatment and individual health circumstances.
This does not mean that a short course of omeprazole is something to worry about. It simply means that if you continue taking it for a long time, your treatment should be reviewed from time to time.
How to Take Your Capsules Correctly
Swallow gastro resistant capsules whole with water. Do not chew or crush them because the medicine inside is designed to pass through the stomach before being released.
Some omeprazole capsules can be opened if you have difficulty swallowing. The pellets inside must not be chewed or crushed, and the instructions for how to take them can vary between products. Check the leaflet for your particular medicine or ask a pharmacist before opening the capsule.
If you regularly find capsules difficult to swallow, speak to your pharmacist or prescriber. Depending on the product available, another formulation may be suitable.
Common Side Effects to Be Aware Of
Common side effects of omeprazole can include headache, nausea, diarrhoea, stomach pain, constipation and increased wind (flatulence). These side effects do not affect everyone.
You may notice some of these effects when you first start treatment. They do not automatically mean that anything is wrong, but speak to a healthcare professional if they are severe, persistent or worrying.
Serious side effects are much less common. Seek urgent medical attention if you develop signs of a serious allergic reaction, such as difficulty breathing or swelling of the lips, mouth, tongue or throat, or if you develop a severe skin reaction such as blistering or peeling.
If 20mg Doesn't Feel Like Enough
If your symptoms are not adequately controlled, your prescriber may review your symptoms, diagnosis, treatment duration and dose.
Depending on the condition being treated, a higher dose such as 40mg once daily may be appropriate. For severe oesophagitis, UK product information recommends omeprazole 40mg once daily, while NICE recommends a full dose PPI for 8 weeks to help heal severe oesophagitis.
Do not increase your dose yourself. If 20mg does not seem to be helping, speak to your prescriber or pharmacist so they can decide whether your dose, treatment or diagnosis needs reviewing.
When to Seek Medical Advice
- Difficulty swallowing, or pain when swallowing, that is new or getting worse
- Unexplained weight loss alongside your reflux symptoms
- Vomiting blood, or passing dark, tarry stools
- Persistent vomiting
- A lump or mass in your upper abdomen
These symptoms are not typical features of uncomplicated acid reflux and may need further assessment. Do not assume that they are simply part of your reflux or a side effect of omeprazole. NHS guidance also advises speaking to a GP if you are worried about your symptoms or if symptoms are getting worse or not improving.
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 for the next dose, skip the missed dose and take your next dose at the usual time. Do not take two doses to make up for a forgotten dose.
If you accidentally take more omeprazole than prescribed, speak to your doctor or pharmacist for advice. If you are concerned that you have taken too much medicine, NHS 111 can also provide advice.
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 |
Some low strength omeprazole products are available from pharmacies without a prescription for short term treatment. If you bought omeprazole without a prescription, do not take it for longer than 14 days without speaking to a doctor.
Medical Disclaimer
This page provides general information for people starting omeprazole. It is not a substitute for personalised medical advice.
Speak to a healthcare professional before changing your dose or continuing treatment if you have other medical conditions, take other medicines or have concerns about your symptoms. Tell your prescriber or pharmacist about all medicines and supplements you take, as omeprazole can interact with some medicines.
Do not change your dose yourself. If you are unsure about how to take omeprazole or whether you should continue taking it, ask your prescriber or pharmacist.
