Omeprazole
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Omeprazole is a proton pump inhibitor (PPI) used to treat conditions linked to excess stomach acid, including acid reflux, gastro oesophageal reflux disease (GORD), and stomach or duodenal ulcers. For many adult conditions, 40mg once daily is a higher dose that may be prescribed when a lower dose is not enough or when the condition needs more intensive treatment. However, 40mg is not an absolute maximum for every condition. Higher doses may be used for specific conditions such as Zollinger Ellison syndrome under specialist supervision.
Omeprazole works by reducing the amount of acid produced by the stomach. This can help relieve symptoms and allow acid related damage to heal.
For adults in the UK looking for guidance on omeprazole dosing, whether prescribed or bought from a pharmacy, this guide explains the usual adult doses, when once or twice daily treatment may be used, and what may be different for people who need extra care, including during pregnancy, breastfeeding, in older age, or with liver problems. It also explains what to do if you accidentally take too much and when to speak to a healthcare professional.
Treatment suitability depends on an individual clinical assessment, and your prescriber will confirm the appropriate dose for your circumstances.
What Is the Maximum Dose of Omeprazole for Adults?
There is no single maximum dose that applies to every adult or every condition.
For many common conditions, including GORD, reflux oesophagitis, stomach ulcers and duodenal ulcers, doses of up to 40mg once daily may be used. For severe reflux oesophagitis, UK product information recommends 40mg once daily. For symptomatic GORD, the recommended dose is usually 20mg daily, although some people may respond to 10mg.
Higher doses are used for some specific conditions. In Zollinger Ellison syndrome, for example, the starting dose is usually 60mg daily and the dose can be adjusted according to the person's needs. UK product information reports doses of 20mg to 120mg daily in some patients. When the dose is above 80mg daily, it should be divided into two doses.
This means you should not treat 40mg as a universal maximum or increase your dose without speaking to your prescriber.
Can I Take 3 Omeprazole a Day?
It depends on the strength of the capsules or tablets and the treatment you have been prescribed.
If you are taking 20mg capsules, three capsules would give you 60mg in one day. That is higher than the usual dose used for GORD, ordinary heartburn and many stomach or duodenal ulcer treatments. It may be used for certain specialist conditions, but it should not be taken simply because your usual dose is not controlling your symptoms.
If your current dose is not helping enough, speak to your prescriber rather than adding another capsule yourself. They may review your symptoms, check how you are taking the medicine and consider whether a different dose, another treatment or further investigation is needed.
Can I Take 40mg of Omeprazole at Once?
Yes, 40mg once daily is a recognised dose for several adult conditions. For example, UK product information recommends 40mg once daily for severe reflux oesophagitis and for some ulcers that do not respond adequately to the standard dose.
However, 40mg once daily is not the correct dose for everyone. For uncomplicated symptomatic GORD, 20mg daily is the usual recommended dose, with the dose adjusted according to the person's response.
Do not change from 20mg to 40mg yourself if your symptoms are continuing. Your prescriber can decide whether a higher dose is appropriate.
Is It OK to Take 2 20mg Omeprazole a Day?
Two 20mg doses give a total of 40mg, but that does not mean everyone prescribed 40mg should automatically take 20mg in the morning and 20mg in the evening.
For many conditions, 40mg is prescribed as a single daily dose. Twice daily treatment is used for some conditions and treatment plans, including certain H. pylori eradication regimens and higher dose specialist treatment. The exact schedule depends on why you are taking omeprazole.
If your prescription says 40mg once daily, take it as prescribed rather than splitting it into two doses. If your prescription says 20mg twice daily, follow that schedule.
Can Omeprazole Be Taken Twice a Day?
Yes. Omeprazole can be prescribed once or twice a day, depending on the condition and treatment plan. NHS guidance advises taking a once daily dose at around the same time each morning, or a twice daily dose at around the same time each morning and evening.
Twice daily treatment is used for some H. pylori eradication regimens, where omeprazole is taken with antibiotics. It can also be used when a higher total daily dose is needed for certain conditions.
Do not change from once daily to twice daily treatment because your symptoms have returned later in the day. Speak to your prescriber or pharmacist first.
If you miss a dose, take it when you remember unless it is nearly time for your next dose. If it is nearly time, skip the missed dose and take the next one as usual. Do not take two doses together to make up for a missed dose.
What Happens If I Take a Double Dose of Omeprazole?
Taking an extra dose of omeprazole is unlikely to cause problems in many cases, according to NHS guidance. However, you should get medical advice if you have taken more than the amount stated on your packet, leaflet or prescription.
You may notice side effects such as stomach discomfort, nausea, dizziness or headache. If you feel unwell or are worried about the amount you have taken, contact NHS 111, your GP or a pharmacist.
Seek urgent medical help if you develop signs of a serious allergic reaction, such as swelling of the throat or tongue or difficulty breathing.
If you miss a dose, do not take an extra dose to make up for it. Follow the missed dose instructions for your medicine instead.
Omeprazole Doses for Adults by Condition (Including Gastroesophageal Reflux Disease)
| Condition | Typical dose | Higher or maximum dose used in some cases |
|---|---|---|
| Symptomatic GORD | 20mg once daily | Up to 40mg once daily may be used depending on the clinical situation |
| Reflux oesophagitis | 20mg once daily | 40mg once daily for severe oesophagitis |
| Stomach ulcer | 20mg once daily | 40mg once daily in some cases |
| Duodenal ulcer | 20mg once daily | 40mg once daily if the ulcer responds poorly to standard treatment |
| H. pylori eradication | 20mg twice daily with appropriate antibiotics | 40mg total daily omeprazole |
| Zollinger Ellison syndrome | Usually 60mg once daily initially | Individually adjusted, with 20mg to 120mg daily reported |
This table is a general guide and is not a personal dosing plan. The dose and length of treatment depend on your diagnosis and individual circumstances.
If you accidentally take more than prescribed, follow NHS advice and seek medical help if you have taken more than the amount stated on your packet, leaflet or prescription.
Who Can Take Omeprazole? Dosing for Special Groups
Older Adults
Older adults can usually take standard doses of omeprazole, and UK product information does not recommend a routine dose adjustment based on age alone.
However, longer term PPI treatment may need regular review. NHS guidance notes that the risk of some serious side effects can be higher with long term use, including weakened bones and certain nutritional problems.
Pregnancy and Breastfeeding
NHS guidance says omeprazole can usually be taken during pregnancy, but you should check with a pharmacist or doctor before taking it. There is more pregnancy safety information available for omeprazole than for some other PPIs, which is one reason it may be recommended during pregnancy when a PPI is needed. UKTIS states that available evidence does not show an increased risk of congenital malformations following PPI exposure in pregnancy.
Omeprazole can also usually be taken while breastfeeding. NHS Specialist Pharmacy Service lists omeprazole as a preferred PPI during breastfeeding because it passes into breast milk in very small amounts. As a precaution, a healthcare professional may advise watching the baby for symptoms such as diarrhoea, constipation, vomiting or a rash.
If you are pregnant or breastfeeding, speak to a healthcare professional before starting, stopping or changing your dose.
Children
Omeprazole can be prescribed for children over one year of age and weighing at least 10kg for certain conditions, including reflux oesophagitis and symptoms of GORD. The dose is based on age, weight and the condition being treated rather than the standard adult doses.
Children should not be given an adult dose unless it has been specifically prescribed for them.
Liver and Kidney Conditions
People with liver problems may need a lower dose of omeprazole. UK product information states that 10mg to 20mg daily may be sufficient in people with impaired liver function.
A routine dose adjustment is generally not needed for people with impaired kidney function. However, you should still tell your prescriber if you have kidney or liver problems so they can check that omeprazole is suitable for you.
Drug Interactions Worth Knowing
Omeprazole can interact with some medicines, so it is important to tell your prescriber or pharmacist about everything you take.
One important interaction is with clopidogrel. NHS Specialist Pharmacy Service advises avoiding omeprazole with clopidogrel because omeprazole can reduce the formation of the active form of clopidogrel. Lansoprazole, pantoprazole or rabeprazole may be used instead when a PPI is needed.
Omeprazole can also interact with medicines such as warfarin, digoxin, phenytoin and some HIV medicines. Tell your healthcare professional about prescription medicines, over the counter medicines, supplements and herbal remedies before starting treatment.
Available Treatment Options
Before taking omeprazole, tell your healthcare provider about any other medicines you use, particularly medicines such as warfarin or clopidogrel.
EverydayMeds stocks omeprazole 20mg capsules, including gastro resistant capsule formulations taken by mouth, and Losec MUPS 20mg gastro resistant tablets, alongside lansoprazole 15mg capsules and orodispersible tablets, pantoprazole, esomeprazole and rabeprazole.
Some omeprazole products are available as liquids or tablets that can be dispersed in water. The available formulation depends on the product. If you have difficulty swallowing capsules or tablets, ask a pharmacist or prescriber whether another formulation may be suitable.
Famotidine tablets are an H2 receptor antagonist and work differently from PPIs. They may be considered as an alternative in some situations.
Omeprazole can also affect the results of some medical tests, so tell your healthcare professional that you are taking it before having tests or investigations.
How to Get Omeprazole Through EverydayMeds
Getting omeprazole through EverydayMeds starts with a short online questionnaire covering your symptoms, medical history and current medicines. The information is reviewed by a UK registered prescriber, who assesses whether omeprazole is suitable and what dose may be appropriate.
Please include details of any other medicines, supplements or health conditions during the consultation. If omeprazole is not suitable for you, the prescriber can advise whether another treatment may be more appropriate.
