Sometimes omeprazole is taken for a rare illness caused by a tumour in the pancreas or gut called Zollinger-Ellison syndrome.
Omeprazole comes as capsules, tablets and as a liquid that you swallow (this is made to order).
All types of omeprazole are available on prescription. You can buy the lowest strength 10mg tablets and capsules from pharmacies.
- It's usual to take omeprazole once a day in the morning.
- For severe illness, you can take it twice a day – in the morning and in the evening.
- Common side effects include headaches, diarrhoea and stomach pain. These tend to be mild and go away when you stop taking the medicine.
- If you're self-treating with omeprazole, do not take it for longer than 2 weeks without checking with a doctor.
Who can and cannot take omeprazole
Omeprazole can be taken by adults, including pregnant and breastfeeding women.
Omeprazole can be taken by children and babies if it's been prescribed by a doctor.
To make sure omeprazole is safe for you, tell your doctor if you:
- have had an allergic reaction to omeprazole or any other medicines in the past
- have liver problems
- are due to have an endoscopy
Ask your doctor if you should stop taking omeprazole a few weeks before your endoscopy. This is because omeprazole may hide some of the problems that would usually be spotted during an endoscopy.
How and when to take omeprazole
It's usual to take omeprazole once a day, first thing in the morning. It does not upset the stomach, so you can take it with or without food.
If you take omeprazole twice a day, take 1 dose in the morning and 1 dose in the evening.
The usual dose to treat:
- indigestion is 10mg to 20mg a day
- heartburn and acid reflux is 20mg to 40mg a day
- stomach ulcers is 20mg to 40mg a day
- Zollinger-Ellison syndrome is 20mg to 120mg a day
Doses are usually lower for children and people with liver problems.
Tablets and capsules
Each tablet or capsule contains 10mg, 20mg or 40mg of omeprazole.
Swallow tablets and capsules whole with a glass of water or juice.
If you have problems swallowing capsules, you can open some brands of omeprazole capsules and mix the granules inside with a small amount of water or fruit juice, or sprinkle them on soft food, such as yoghurt or apple puree.
Do not open capsules that have a special coating (like those made by Dexel). Talk to your pharmacist if you're not sure whether you can open your capsules.
Omeprazole also comes as a tablet that melts in your mouth.
You can buy omeprazole 10mg tablets and capsules from pharmacies.
They're the same as omeprazole 10mg tablets and capsules that you get on prescription, but they're meant to be taken only by adults, and only for up to 4 weeks.
Liquid omeprazole can be prescribed by a doctor and made to order for children and people who cannot swallow capsules or tablets.
It'll come with a syringe or spoon to help you take the right amount. If you do not have a syringe or spoon, ask your pharmacist for one.
Do not use a kitchen teaspoon as it will not give the right amount.
Will my dose go up or down?
Sometimes your doctor will increase your dose of omeprazole if it is not working well enough.
Depending on the reason you take omeprazole, you may take a higher dose to begin with, usually for a few weeks.
After this, your doctor may recommend that you take a lower dose.
How long will I take it for?
If you bought the medicine yourself from a pharmacy, tell your doctor if you feel no better after taking omeprazole for 2 weeks.
They may want to do tests to find out what's causing your symptoms or change you to a different medicine.
Depending on your illness or the reason you're taking omeprazole, you may only need it for a few weeks or months.
Sometimes you might need to take it for longer, even for many years.
Some people do not need to take omeprazole every day and take it only when they have symptoms.
Once you feel better (often after a few days or weeks), you can stop taking it.
But taking omeprazole in this way is not suitable for everyone. Talk to your doctor about what's best for you.
What if I forget to take it?
- If you usually take it once a day, take the missed dose as soon as you remember, unless it's within 12 hours of your next dose, in which case skip the missed dose.
- If you usually take it twice a day, take the missed dose as soon as you remember, unless it's within 4 hours of your next dose, in which case skip the missed dose.
Do not take a double dose to make up for a forgotten dose.
If you forget doses often, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.
What if I take too much?
It's very unlikely that taking 1 or 2 extra doses by accident will cause any problems.
But you should check with your doctor if you have taken too much and have any of these symptoms:
- flushed skin
- feeling sweaty
- a fast heartbeat
- feeling sleepy
- blurred vision
- feeling confused or agitated
Most people who take omeprazole do not have any side effects. If you do get a side effect, it's usually mild and will go away when you stop taking omeprazole.
Common side effects and self-help advice
These common side effects happen in more than 1 in 100 people.
Omeprazole may also make you feel dizzy or sleepy. Some people might find it difficult to fall asleep.
It may also cause an itchy or lumpy skin rash, or make your feet or ankles swell.
Talk to your doctor or pharmacist if the side effects bother you or do not go away.
Serious side effects
Serious side effects are rare and happen in less than 1 in 1,000 people.
Call a doctor straight away if you have:
- yellow skin, dark pee and tiredness – these can be signs of liver problems
- joint pain along with a red skin rash, especially in parts of your body exposed to the sun, such as your arms, cheeks and nose – these can be signs of a rare condition called subacute cutaneous lupus erythematosus. This can happen even if you have been taking omeprazole for a long time
Serious allergic reaction
In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to omeprazole.
These are not all the side effects of omeprazole. For a full list, see the leaflet inside your medicines packet.
Pregnancy and breastfeeding
Usually, omeprazole is safe to take during pregnancy and while breastfeeding.
Omeprazole and pregnancy
If you're pregnant, it's always better to try to treat indigestion without taking a medicine.
Your doctor or midwife will first advise that you try to ease your symptoms by eating smaller meals more often and avoiding fatty and spicy foods.
They may also suggest raising the head of your bed 10 to 20cm by putting something under your bed or mattress, so that your chest and head are above your waist. This helps stop stomach acid travelling up towards your throat.
If lifestyle changes do not work, you may be recommended a medicine like omeprazole.
Omeprazole and breastfeeding
Omeprazole is safe to take while you're breastfeeding. It passes into breast milk, but only in small amounts that are not harmful to the baby.
But if your baby is premature or has health problems, check with your doctor first.
For more information about how omeprazole can affect you and your baby during pregnancy, read this leaflet on the Best Use of Medicines in Pregnancy (BUMPs) website.
Cautions with other medicines
Some medicines and omeprazole can affect each other and make it more likely that you'll have side effects.
Tell your doctor if you're taking these medicines before you start omeprazole treatment:
- heart medicines, such as digoxin
- cilostazol (treats peripheral arterial disease)
- antifungal medicines, such as itraconazole, posaconazole and voriconazole
- methotrexate (treats psoriasis and rheumatoid arthritis)
- HIV medicines
- phenytoin (an anti-epilepsy medicine)
- rifampicin (an antibiotic)
- blood thinning medicines, such as clopidogrel and warfarin
These are not all the medicines that may not mix well with omeprazole. For a full list, see the leaflet inside your medicine packet.
Mixing omeprazole with herbal remedies and supplements
Do not take St John's wort, the herbal remedy for depression, while you're taking omeprazole.
St John's wort may stop omeprazole working as well as it should.