Omeprazole

What is omeprazole used for?

Omeprazole is a medication that belongs to a class of drugs known as proton pump inhibitors (PPIs) which treat certain conditions in the stomach often caused by an excess of acid. [1]  

It is most commonly used to treat indigestion, heartburn, and acid reflux, but it can also be used for conditions like: 

• Gastroesophageal reflux disease (GERD) - a condition where stomach acid frequently flows back into the oesophagus 

• Stomach ulcers - sores that develop on the lining of the stomach, small intestine, or oesophagus. 

• Zollinger-Ellison syndrome – a condition where the stomach produces too much acid 

• Erosive oesophagitis – inflammation and damage to the oesophagus caused by stomach acid 

• Helicobacter pylori infection - often treated in combination with antibiotics to eradicate the bacteria[1] 

How does omeprazole work?

It works by reducing the amount of acid produced in the stomach, making it effective in treating various acid-related conditions[1]. 

Who can take omeprazole?

Omeprazole can be taken by most adults and children over the age of one year. However, you should consult a doctor or pharmacist first if you have: 

• Liver disease 

• Osteoporosis or low bone mineral density 

• Low levels of magnesium in your blood 

• An endoscopy scheduled 

• Allergies to omeprazole or similar medications[2][4]

Please tell your doctor or pharmacist about any conditions you may have before starting omeprazole, and always follow the instructions in the Patient Information Leaflet[2]. 

How do you take omeprazole?

Omeprazole is usually taken once daily, preferably in the morning before a meal, in tablet or capsule form. It should be swallowed whole with water and not crushed or chewed. If you have difficulty swallowing capsules, you can open them and mix the contents with a small amount of applesauce[4][5].* 

What is the typical dosage of omeprazole?

The typical dosage of omeprazole varies depending on the condition being treated: 

• Indigestion – 10mg to 20mg a day 

• Heartburn & acid reflux – 20mg to 40mg a day 

• GERD – 20mg once daily for 4-8 weeks 

• Stomach ulcers - 20mg to 40mg once daily  

• Zollinger-Ellison Syndrome - 20mg to 120mg once daily, adjusted as needed 

• H. pylori eradication - 20mg twice daily in combination with antibiotics for 7-10 days [5] 

What do you do if you take too much omeprazole?

It's very unlikely that one or two extra doses will cause you any problems. But if you suspect an overdose, seek immediate medical attention. Symptoms of overdose may include confusion, dizziness, drowsiness, diarrhoea, nausea, vomiting, abdominal pain and headache[6][7][11]. 

What do you do if you forget to take your omeprazole dose?

If you miss a daily dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and resume your regular schedule. If you usually take it twice a day, take the missed dose as soon as you remember, but if it’s 4 hours or less until your next, do not take it and take next dose as scheduled. Do not double the dose to catch up[8]. 

What are the side effects of omeprazole?

The most common side effects of Omeprazole include: 

• Headache 

• Nausea 

• Diarrhoea 

• Stomach pain 

• Gas 

• Vomiting[3][2] 

The most serious side effects of omeprazole, though rare, can include: 

• Severe allergic reactions (e.g., rash, itching, swelling) 

• Severe dizziness 

• Trouble breathing 

• Signs of kidney problems (e.g., change in the amount of urine) 

• Symptoms of a low magnesium blood levels (e.g., muscle cramps, irregular heartbeat)[3][2] 

If you experience any of these side effects, stop taking omeprazole and consult your GP or call 111.

The information provided in the side effects section is not a comprehensive list of all possible side effects associated with this medication. For a complete list of side effects, please refer to the Patient Information Leaflet (PIL) provided with your medication or consult your healthcare professional[2].

If you experience any side effects, including those not listed, you are encouraged to report them via the Yellow Card Scheme or contact your doctor, pharmacist, or nurse. This information is intended as a summary for general awareness and does not replace professional medical advice. 

Medicines you can't take with omeprazole

Omeprazole can interact with several medications, including[9]: 

• Warfarin - increases the risk of bleeding. 

• Clopidogrel - reduces the effectiveness of this antiplatelet drug. 

• Certain antifungals - such as ketoconazole and itraconazole. 

• HIV medications - such as atazanavir and nelfinavir. 

Always inform your doctor or pharmacist about all medications and supplements you take before you start a new medicine, and follow the instructions in the Patient Information Leaflet[2]. 

Frequently asked questions about omeprazole

Can I take omeprazole long-term? 

Long-term use of omeprazole should be monitored by a doctor or pharmacist due to potential risks such as vitamin B12 deficiency, magnesium deficiency, and bone fractures[10]. 

How long does it take for omeprazole to work? 

You should start to improve within two to three days, but it can take up to four weeks for omeprazole to work fully, and you may still have some acid symptoms in this period. 

If you don’t improve at all after two weeks, speak to your doctor or pharmacist. 

What if I’m not getting better using omeprazole? 

Speak to your doctor or pharmacist, who may consider different treatments, like pantoprazole or lansoprazole. 

Can I take antacids with omeprazole? 

Yes, antacids can be taken with omeprazole if needed[10]. 

Should I drive or cycle while taking omeprazole? 

It can cause dizziness, tiredness, and blurred vision. If you experience any of these symptoms, do not drive, cycle, or use heavy machinery. 

Can I drink alcohol and take omeprazole? 

Although alcohol doesn’t affect the way omeprazole works, you should try to avoid it where possible as alcohol makes your stomach produce more acid than normal. 

What else can I do improve my symptoms? 

Making lifestyle changes can help ease your symptoms. You should try to: 

• Maintain a healthy weight with a balanced diet 

• Avoid foods that cause excess acid, like rich, spicy, or fatty foods, and acidic foods, like citrus fruit, fizzy drinks, and salad dressings 

• Stop smoking  

• Reduce caffeine and alcohol consumption  

• Try not to eat 3 hours before you sleep 

• Prop your head and shoulders up when you sleep 

Is omeprazole safe during pregnancy? 

Consult your doctor or pharmacist before taking omeprazole during pregnancy[2]. 

Can I stop taking omeprazole? 

Is it usually safe to come off omeprazole without reducing your dose, but if you’ve been taking it for a while, speak to your doctor or pharmacist first.

For the official NHS guide to omeprazole, visit their website.