• Omeprazole


Medication features

  • Short term (4-5 day) Treatment
  • 10mg and 20mg Omeprazole available
  • ONCE or TWICE daily as required
  • See GP if symptoms persist


Omeprazole Tablets Online

You can request to buy Omeprazole for acid reflux from our UK registered online pharmacy and doctor service. No prescription is required, however, you will need to complete an online assessment, so our doctors can issue a prescription to our pharmacy. If the doctors approve your order, a prescription is passed to our pharmacy, which will then dispense and dispatch your medication.

About Omeprazole

Omeprazole is a drug that reduces the amount of acid the stomach makes. It is a proton pump inhibitor (PPI). Omeprazole can be used to treat a number of conditions. It is most often used to treat indigestion and heartburn/acid reflux.

Acid reflux, also known as heartburn, occurs when stomach acid travels up the gullet (oesophagus) to the throat. This can cause a burning sensation in the chest and leave an unpleasant taste in the back of the mouth. If acid reflux continues long term, it is called gastroesophageal reflux disease (GERD or GORD).

Indigestion, also called dyspepsia, is discomfort in the stomach that can cause you to feel bloated or sick. Acid reflux is also a symptom of indigestion.

Omeprazole is very commonly used to treat these conditions and is effective at improving symptoms of heartburn and indigestion.

Acid reflux can sometimes be caused by serious diseases. Please talk to your doctor or pharmacist if lifestyle changes or over the counter medicines do not improve symptoms, your symptoms persist longer than 5 days despite taking omeprazole, you have heartburn frequently for 3 weeks or more or if there are other symptoms, like food getting stuck in the throat, being sick often or unintended weight loss.

Your GP can run tests to rule out serious causes of acid reflux.

When filling out our online form make sure to list all of your symptoms, even if they do not seem linked to acid reflux.

Omeprazole can also be used for:

  • Erosive esophagitis (stomach acid can damage the oesophagus long term)
  • Zollinger Ellison syndrome
  • Stomach ulcers
  • H.Pylori stomach infections (omeprazole is taken for 7 or 14 days alongside antibiotics)

Certain factors can cause or worsen acid reflux and indigestion:

  • Fatty, rich or spicy foods
  • Caffeinated drinks, such as coffee or fizzy drinks
  • Alcohol
  • Being overweight
  • Smoking
  • Stress
  • Certain medications, such as ibuprofen

How does Omeprazole work?

The lining of the stomach contains proton pumps. These pump acid into the stomach to help digest food. Acid reflux is caused by this acid travelling from the stomach to the gullet and sometimes to the throat.

Omeprazole is a proton pump inhibitor. This means it decreases the amount of acid produced by the proton pumps. This decreases the amount of acid in the stomach and improves indigestion and heartburn symptoms.

Omeprazole is very effective at reducing the amount of acid the stomach produces. This makes it an effective treatment for acid reflux.

Omeprazole capsules are delayed release to make sure the medication enters the bloodstream.

Omeprazole capsules are available in strengths of 10mg or 20mg. Our doctors can also prescribe orodispersible versions of omeprazole under the brand name Losec MUPS. It can also come as an oral suspension. These are useful if a patient has difficulty swallowing capsules.

Omeprazole 20mg and Omeprazole 10mg

The usual starting dose is 10mg once daily. If this dose is not sufficiently controlling your symptoms, but you have seen some improvement, your doctor may consider increasing up to Omeprazole 20mg. If symptoms are still not controlled, your doctor may consider prescribing twice-daily doses.

Ideally, you use the lowest dose required to control the symptoms. This will minimise the side effects you may experience. Each person’s dose is dependent on their condition and should be decided by a doctor.

Omeprazole Dosage


Omeprazole 10mg and 20mg

Omperazole Dose

The most common dosage is ONE capsule first thing in the morning with a glass of water. Swallow the capsule whole to ensure the medicine absorbs properly. May be taken with or without food. If you expect to experience acid reflux from your breakfast, it is best to take the capsule 30 minutes before breakfast.

If your GP has advised a twice-daily dosage, you may take ONE both morning and evening.

If you forget to take a dose, take it as soon as you remember unless it is nearly time for your next dose. If this happens, skip the missed dose and take the remaining capsules as normal. A double dose should not be taken.

Omeprazole Summary


Take ONE capsule in the morning or as directed

Type of medicine

Proton pump inhibitor


Reduces the amount of stomach acid in the stomach, relieving acid reflux symptoms

Available Size

28 to 56 capsules


10mg & 20mg

Active Ingredient



From £9.95

Side Effects

Can include stomach pain, nausea, headache, diarrhoea

Omeprazole Prices

10mg x 28 Capsules


10mg x 56 Capsules


20mg x 28 Capsules


20mg x 56 Capsules


Omeprazole Alternatives

There are several other prescription and non-prescription treatments for acid reflux. The other most common prescription treatments are other medicines in the same family (PPIs) Pantoprazole, Rabeprazole and Lansoprazole.

View our full range of prescription acid reflux treatments here

Over the counter treatments for acid reflux work by creating a barrier on top of the stomach to prevent acid reflux. These treatments include Rennie, Peptac, Gaviscon and Alka Seltzer.

View our full range of over the counter acid reflux treatments here

Certain lifestyle changes can be used alongside omeprazole or other medications to improve symptoms: 

  • Avoid eating 3 hours before bedtime
  • Eating smaller meals
  • Losing weight if overweight
  • Raising the head of the bed (so your chest is above the level of your waist)

Omeprazole side effects

As with all medications, there are some side effects, although not everybody gets them. Some of the side effects of Omeprazole are stomach pain, headache, diarrhoea and nausea. Some of these may be caused by the acid reflux itself.

A full list of side effects can be seen in the patient information leaflet and it is always advised you read this prior to taking any medication.

If omeprazole is taken long term (over 1 year) it can increase the risk of certain side effects:

  • Magnesium deficiency (can occur after 3 months of treatment)
  • Bone fractures or joint pain
  • Vitamin B12 deficiency
  • Gut infections (increased risk of clostridium difficile)

Your GP may want to monitor you more closely if you take omeprazole long-term.


Tyson Wilkman, Clinical Pharmacist


Tyson Wilkman

RoleClinical Pharmacist
Qual.Bachelor of Pharmacy (Honours)
AboutTyson started with Simple Online Pharmacy in 2021. He's responsible for helping author and review accurate site content. He works with our GPs to make sure all aspects of the medicines are covered.


How long should I take Omeprazole?

Without seeing a GP for a check-up, Omeprazole should only be taken for 4-5 days to help control acid reflux. If your symptoms persist, this may be indicative of a more serious condition, and you should see your GP for a full checkup.

How long does Omeprazole take to work?

Omeprazole should work quickly for heartburn although this varies between patients. Some people find symptoms improve after the first dose although it can take up to 4 weeks for the full effect to be seen. If symptoms have not improved after 5 days of taking omeprazole, talk to your doctor/GP.

Can I take Omeprazole with Gaviscon or other heartburn medication?

Antacids like Gaviscon can be used with omeprazole but should be taken at least 2 hours after omeprazole. If you find you need to use an antacid often while taking omeprazole, please speak to your doctor or pharmacist. Apart from antacids, do not take other heartburn medication with omeprazole.

Can you buy Omeprazole over the counter?

No, Omeprazole is a prescription-only medicine in the UK. You can buy omeprazole online in the UK using a registered UK doctor and pharmacy service. An assessment is completed online and a UK doctor will decide whether you are suitable for treatment and issue a prescription filled by the pharmacy.


Treatment Comparison

Omeprazole / LosecRanitidine / Zantac
IngredientOmeprazole 10 or 20mgRanitidine 150 or 300mg
Mechanism of ActionPPI - reduces acid in stomachH2 Blocker - reduces acid in stomach
Common Side EffectsDiarrhoea, headache, nausea, and vomiting.Diarrhoea, headache, nausea, and vomiting.
DosageOne tablet up to twice daily as requiredOne tablet up to twice daily as required


Info Leaflet

Before taking any medication, it is important to read the Patient Information Leaflet.


Warnings and Precautions

Interactions with other medication

When filling out our online form, make sure to list any medication you currently take.

Some drugs interact with omeprazole and may cause side effects or reduce how well one or both medications work. 

Omeprazole may reduce the effectiveness of the blood thinner clopidogrel. Patients who take clopidogrel should be prescribed a different PPI such as lansoprazole.

Other medicines which may interact are listed below:

  • Medications for HIV
  • Methotrexate (used to treat autoimmune disease and cancer)
  • Ketoconazole, itraconazole, rifampicin (used to treat infections)
  • Digoxin (used to treat heart problems)
  • Warfarin (used as a blood thinner)
  • Other medication for heartburn such as antacids

Other medical conditions

When filling out our online form, make sure to mention any medical conditions that you have.

Omeprazole may not be safe for everyone, especially those who:

  • Have had an allergic reaction to omeprazole or any other medicines in the past
  • Have liver disease
  • Are due to have an endoscopy
  • Have B12 deficiency or magnesium deficiency

Omeprazole and Alcohol

While it is safe to drink alcohol with Omeprazole, it may worsen acid reflux symptoms and should be avoided if you find alcohol worsens your symptoms. Alcohol may also increase the dizziness experienced with Omeprazole. If this occurs, avoid alcohol.

Omeprazole in pregnancy and breastfeeding

Is Omeprazole safe in pregnancy? Omeprazole is considered reasonably safe in pregnancy however if possible, there should be an attempt to control symptoms with lifestyle changes first.

Is Omeprazole safe while Breastfeeding? There is very little evidence to show whether Omeprazole is safe in breastfeeding. For this reason, your doctor must consider the risk and benefits of the treatment before use.

For a full list of the warnings and precautions for omeprazole, read the patient information leaflet.

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Prices From £9.95
As low as £0.27 / Capsule

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Medication Simple Online Pharmacy
20mg x56 - Capsules £15.95
20mg x28 - Capsules £10.95
10mg x56 - Capsules £14.95
10mg x28 - Capsules £9.95

Ranitidine 150mg Tablets

Medication Simple Online Pharmacy
60 - Tablets (150mg) £14.95
30 Tablets (150mg) £9.95


Medication Simple Online Pharmacy
15mg x28 £16.95
15mg x14 £11.95
30mg x14 £12.95
30mg x28 £17.95
15mg Orodispersible x28 £24.95
15mg Orodispersible x14 £14.95
30mg Orodispersible x14 £16.95
30mg Orodispersible x28 £26.95


Medication Simple Online Pharmacy
20mg x56 - Capsules £32.99
20mg x28 - Capsules £18.99
10mg x28 - Capsules £14.99

Losec MUPS Tablets

Medication Simple Online Pharmacy
20mg x28 - Tablets £28.99


Medication Simple Online Pharmacy
20mg x14 £13.50
20mg x28 £16.50
20mg x56 £19.50
20mg x112 £29.50
40mg x14 £14.50
40mg x28 £17.50
40mg x56 £20.50
40mg x112 £31.50


Medication Simple Online Pharmacy
20mg x14 £12.50
20mg x28 £18.50
20mg x56 £22.50
20mg x112 £29.50
40mg x14 £13.50
40mg x28 £19.50
40mg x56 £23.50
40mg x112 £30.50


Medication Simple Online Pharmacy
10mg x14 £11.50
10mg x28 £16.50
10mg x56 £19.50
10mg x112 £33.50
20mg x14 £12.50
20mg x28 £17.50
20mg x56 £20.50
20mg x112 £34.50