What is Omeprazole? 

Omeprazole is a common proton pump inhibitor (PPI) that greatly lowers stomach acid by blocking the H⁺/K⁺-ATPase enzyme in stomach cells. It is mainly used for gastroesophageal reflux disease (GERD), peptic and duodenal ulcers, and conditions like Zollinger–Ellison syndrome. It comes in different strengths and as delayed-release capsules or tablets, which helps it reach the small intestine for better absorption.

Although generally well tolerated, common side effects include headache, nausea, and stomach discomfort, while long-term use may lead to nutrient deficiencies and an increased risk of bone fractures. Seek immediate help from your GP, NHS111 or A&E to avoid complications.

What is Omeprazole Used For? 

GERD Relief: Omeprazole lowers stomach acid, easing heartburn and reflux symptoms.
Ulcer Healing: It helps peptic and duodenal ulcers heal by reducing harmful acid levels.
Hypersecretory Conditions: It controls conditions like Zollinger–Ellison syndrome by cutting down too much acid production.

At 123Meds, we supply Omeprazole GR Capsules solely for treating acid-related problems like GERD, acid reflux, and peptic ulcers. If you are thinking of using Omeprazole for another condition, please speak to your GP to see if it is a suitable option.

How Omeprazole Works 

Omeprazole works by lowering the acid in your stomach, easing heartburn and letting your stomach heal.

Mechanism of Action: 

Proton Pump Inhibition: Omeprazole permanently binds to the H⁺/K⁺ ATPase enzyme, stopping the last step of acid production.
Reduced Acid Secretion: This blocking causes a large drop in both normal and simulated stomach acid production.
Sustained Effect: The binding lasts a long time, keeping acid low until new enzymes are formed.
When is Gastroesophageal Reflux Disease (GERD) Confirmed, and Medication Needed? 

GERD is diagnosed when a patient has frequent, ongoing symptoms—such as heartburn, acid coming back up, and chest pain—that occur more than twice a week, often confirmed by tests like endoscopy or pH monitoring.

Medicine is needed when changes in lifestyle and diet do not control symptoms, or if complications such as oesophagitis, Barrett’s oesophagus, or ulcers develop. In these cases, proton pump inhibitors like Omeprazole are given to lower acid and help healing, with early diagnosis and correct treatment important to stop further damage to the oesophagus.

Physical causes of GERD:

A weak lower oesophageal sphincter (LES) does not close well, letting stomach acid flow back into the oesophagus.
A hiatal hernia changes the usual shape of the diaphragm and LES, which can cause acid reflux.
High pressure in the abdomen from obesity or pregnancy pushes stomach contents up, causing reflux.
Psychological causes of GERD: 

Long-term stress and anxiety can boost stomach acid and lower the pressure of the lower oesophageal sphincter, making reflux worse.

Depression and emotional distress can make you more sensitive, so reflux symptoms feel stronger.

Symptoms of GERD: 

Ongoing heartburn or a burning chest pain after eating.
Acid coming back up with a sour or bitter taste.
Trouble swallowing or feeling like food is stuck in your throat.
If these symptoms last for several weeks, you should seek help from a medical professional.

A medical check-up, including a review of your history and tests, will help find the cause. Treatment might include medicines like Omeprazole to lower stomach acid and help healing, along with suggested lifestyle changes. Your healthcare provider will create a personalised plan to best treat your condition and stop further problems.

Can Omeprazole Be Purchased Over the Counter? 

In the UK, Omeprazole can be bought over the counter in 10 mg and 20 mg strengths, given as a 14-day course for regular heartburn and mild acid reflux.

The 40 mg strength is not sold OTC and needs a prescription. Always follow the dose instructions on the pack and local advice. If symptoms continue or get worse, speak to your pharmacist or GP for further checks and the right treatment changes.

Alternative Medications 

Omeprazole is a common acid reducer in the UK, but there are other medicines for patients with different needs or preferences. These options might be easier on you, more consistent, or use a different method to manage acid problems.

Lansoprazole: Lansoprazole is a proven proton pump inhibitor in the UK, treating acid-related conditions effectively. It works similarly to Omeprazole and is sold under names like Prevacid. Some people might have better symptom control or find it easier to tolerate because of individual differences in how they process medicine.

Esomeprazole: Esomeprazole, a version of Omeprazole, is made to give steadier acid suppression with less variation between people. It is often given when Omeprazole does not work as well. This medicine gives steady symptom relief and may help healing in reflux conditions.

H2 Receptor Antagonists: H2 blockers like famotidine reduce stomach acid by blocking histamine receptors. In the UK, they are sold over the counter and are used for milder reflux or along with lifestyle changes. This option is good for patients who cannot tolerate PPIs.

If you are unsure about the best treatment for your condition, please speak to your 123Meds prescriber for tailored advice.

How to Take Omeprazole?

Timing: Take Omeprazole 30–60 minutes before breakfast for the best absorption.

Dosage: For mild to moderate reflux, take one 10 mg or 20 mg capsule each day as stated on the pack. Follow the 14-day course. Do not take more than advised, and if your symptoms continue after the course, consult your GP for further checks and treatment changes.

With Food: Take Omeprazole on an empty stomach for best absorption; ideally, 30 to 60 minutes before eating. If you feel upset in your stomach, you can take it with a small snack, but avoid high-fat meals as they might lower its effect.

Avoid: Do not eat high-fat, spicy, or acidic foods right after taking Omeprazole, as these may cause extra acid and lessen the medicine’s effect. Also, avoid alcohol and caffeinated drinks.

If you miss a dose, take it as soon as you remember unless it is almost time for your next dose; then skip the missed dose and continue as usual.

Omeprazole has both active and inactive ingredients that work together to lower stomach acid.

Active Ingredient:

The active part is Omeprazole, usually made as omeprazole magnesium in gastro-resistant capsules. It works by blocking the stomach proton pump, which lowers acid and eases symptoms of acid reflux and ulcers.

Inactive Ingredients:

Inactive parts like microcrystalline cellulose, hypromellose, and magnesium stearate help form the tablet, keep it stable, and control how the medicine is released and absorbed. Inactive ingredients can vary between manufacturers, so please check the packaging or contact us for further assistance.

Omeprazole is usually safe when taken as directed, but like all medicines, it can cause side effects.

Common Side Effects:

• Headache: You might have a mild headache that usually goes away on its own.
• Nausea: You may feel a bit sick, but this usually fades as your body gets used to it.
• Diarrhoea: You might have loose stools for a short time during treatment.
• Constipation: Some people may find it hard to pass stools, which often gets better with changes in diet.
• Stomach Pain: You might feel mild discomfort or cramps in your stomach.
• Flatulence: You may have more gas and bloating, which usually does not need treatment.
• Dizziness: You might feel a bit light-headed, but it usually does not last long.
• Rash: You could get a small skin irritation or redness, which typically goes away on its own.

Less Common Side Effects:

• Low Magnesium Levels (Hypomagnesemia): Long-term use might lower magnesium, which can cause muscle cramps or weakness.
• Vitamin B12 Deficiency: Using it for a long time might affect B12 absorption, causing tiredness or anaemia.
• Interstitial Nephritis: In rare cases, kidney inflammation can happen, needing quick medical care.

If you experience severe or long-lasting side effects such as strong stomach pain, trouble swallowing, or signs of an allergic reaction (swelling, rash, or difficulty breathing), please seek immediate medical assistance by visiting your Accident and Emergency department. Do not ignore these serious symptoms, as quick care can stop serious problems.

Before you begin Omeprazole, make sure you tell your prescriber about any existing conditions so they can decide the best treatment and dose for you.