Omeprazole: uses, dosage and side effects
Omeprazole is a proton pump inhibitor that reduces the amount of acid the stomach produces. It is used for heartburn, reflux and stomach ulcers. Lower-strength packs for short-term heartburn are available from a pharmacy in Ireland without a prescription, while longer treatment and higher strengths are prescription-only. This page explains what it is used for, how it is taken and its side effects.
What omeprazole is used for
Omeprazole reduces stomach acid, and it is used for gastro-oesophageal reflux disease, heartburn and acid regurgitation, for stomach and duodenal ulcers, for oesophagitis caused by acid, and to protect the stomach lining in people who need to keep taking anti-inflammatory painkillers. It is also part of the combination used with antibiotics to clear Helicobacter pylori. It belongs to the group called proton pump inhibitors, which switch off the acid pumps in the stomach lining rather than neutralising acid already there. That mechanism explains what it is not. It is not an antacid for instant relief after a heavy meal, and it is not a treatment for the cause of reflux, which may be weight, alcohol, smoking, late meals or a hiatus hernia. Some symptoms that look like heartburn are not heartburn at all: chest pain that comes on with exertion, spreads to the jaw or arm, or is accompanied by breathlessness or sweating needs emergency assessment, not an acid tablet. Call 112 or 999 in that situation.
Side effects of omeprazole
The effects reported most often are headache, abdominal pain, nausea, constipation, diarrhoea and wind, and most people tolerate the medicine well. Because it changes the acidity of the stomach, long-term use has been associated with a higher risk of gut infections, with low magnesium levels, with reduced vitamin B12 absorption over years, and with a small increase in fracture risk at high doses over long periods. That is why a prescriber reviews long-term treatment rather than leaving it running indefinitely. Some symptoms mean the tablet is the wrong answer and you need assessment instead: difficulty or pain on swallowing, food sticking, vomiting blood or material that looks like coffee grounds, black tarry stools, unintentional weight loss, or a first episode of severe indigestion in an older adult. Seek medical advice urgently for any of these. Also seek help for a severe rash, jaundice, or muscle cramps and an irregular heartbeat, which can be signs of low magnesium.
Dosage and how to take omeprazole
Omeprazole is taken by mouth once a day for most indications, usually in the morning and before a meal, and the capsules or tablets are swallowed whole with water rather than chewed, because the coating is what protects the medicine from stomach acid. Some products can be opened and the contents mixed with a little water or fruit juice for people who cannot swallow capsules; check your own leaflet before doing that. The prescriber sets the strength and the length of treatment, which differ between reflux, ulcer treatment and ulcer prevention. The effect builds over the first days rather than arriving with the first dose, so judge it after a few days rather than after one. If you miss a dose, take it when you remember unless the next one is nearly due. If you have been on it long term, ask a doctor before stopping, because acid can rebound for a while and a planned step down is often easier than an abrupt stop.
Is omeprazole available without a prescription in Ireland?
Partly. Lower-strength omeprazole for the short-term relief of reflux symptoms in adults is available in Irish pharmacies as a pharmacy medicine, which means the pharmacist supplies it after a few questions and no prescription is needed. If that is all you need, you do not have to pay anyone for a consultation: ask at the pharmacy counter. Higher strengths, longer courses, treatment of ulcers and use in children remain prescription-only. The pharmacy route is designed for a short course. If your symptoms come back as soon as you stop, if you have been taking it for weeks on end, or if you have any of the warning symptoms listed above, that is a reason to be assessed rather than to keep buying packs. Omeprazole is not a controlled drug, so it is not excluded from cross-border prescriptions under Article 11(6) of Directive 2011/24/EU, and a prescription from a prescriber elsewhere in the EU or EEA can be presented in an Irish pharmacy.
Renewing an existing omeprazole prescription
If a doctor has already assessed you and prescribed omeprazole as ongoing treatment, and that treatment needs to be continued, you can request a repeat prescription through our medical questionnaire. A doctor reviews what you write and, where continuation is appropriate, issues a cross-border prescription as a PDF by e-mail; you bring the document and photo identification to any pharmacy. There is no PIN code, and there is no video consultation, no telephone appointment and no live chat, because the review is asynchronous. Documents are issued by lek. Damian Wojno, a doctor registered in Poland, PWZ no. 3211301. Before you do that, ask yourself whether you need a prescription at all. For occasional heartburn a pharmacy pack is enough and paying a consultation fee would buy you nothing. The fee of 19,90 € covers the medical consultation, not the issuing of a document. If the doctor declines on medical grounds, the fee is returned. If you do not send documentation the doctor asks for, the consultation counts as carried out and the fee is not refunded. Long-term acid suppression should be reviewed periodically by a doctor who can arrange tests where they are needed.
Cost and reimbursement in Ireland
What omeprazole costs at the counter depends on the strength, the pack, the manufacturer and the pharmacy, and pharmacy-medicine packs bought without a prescription are priced by the pharmacy itself. Generic omeprazole is widely available. We neither sell medicines nor quote prices for them; ask the pharmacist before dispensing if cost matters to you. For prescribed treatment, the HSE runs the medical card scheme and the Drugs Payment Scheme, which caps what a household pays for approved prescribed medicines in a calendar month. A medicine bought over the counter without a prescription generally falls outside those schemes. How a prescription written by a prescriber in another EU country is treated under them is decided by the HSE and applied at the counter, so check with the pharmacy first. Our own charge is the consultation fee described above and is separate from what the pharmacy charges.
Interactions and alcohol
Omeprazole has interactions that matter, and the best known is with clopidogrel: omeprazole can reduce how well clopidogrel works, so the combination is generally avoided and your doctor will choose differently if you take it. It can also affect methotrexate, digoxin, tacrolimus, some antifungals and some HIV medicines, partly because reducing stomach acid changes how well those medicines are absorbed. If you take warfarin your INR may need checking, and if you take citalopram or escitalopram tell the prescriber. Alcohol does not directly interact with omeprazole, but it increases acid production and relaxes the valve at the top of the stomach, so it tends to provoke exactly the symptoms you are treating. The same goes for smoking, large late meals, coffee and lying down soon after eating. Always give the prescriber a full list of your medicines, including anything you bought yourself and any herbal product.
Who should not take omeprazole
Omeprazole is not suitable for anyone who has had an allergic reaction to it or to another proton pump inhibitor, and it must not be combined with certain HIV medicines whose absorption depends on stomach acid. Care is needed if you have liver problems, if you have low magnesium or take a diuretic, if you have osteoporosis or risk factors for it, or if you are due to have tests for stomach conditions, because acid suppression can mask findings and interfere with some tests for Helicobacter pylori. Age and duration matter as well: a first episode of indigestion in an older adult, or symptoms that keep returning, should be assessed rather than suppressed. This is not a complete list. The contraindications and warnings for your specific product are set out in its leaflet and in the summary of product characteristics published by the HPRA, and only a doctor who knows your history can apply them to your situation.
Generic and brand names
Omeprazole is the international non-proprietary name of the active substance. In Ireland it is dispensed mostly as generic omeprazole carrying the manufacturer's name; the original brand name is Losec, and pharmacy packs sold for short-term heartburn carry their own brand names. Whatever is on the box, the active substance and the strength determine the effect. Other proton pump inhibitors, such as pantoprazole, lansoprazole and esomeprazole, work in the same way but are different substances with different interaction profiles, so they are not automatically interchangeable and a switch is a decision for a prescriber. At the counter, check the substance and the strength rather than the brand, since the supplier can change between one prescription and the next. A cross-border prescription names the active substance, which is what allows a pharmacist in another country to dispense the equivalent product authorised there.
Omeprazole in pregnancy and breastfeeding
Heartburn is very common in pregnancy, and omeprazole is one of the medicines a doctor may consider when diet changes and simple antacids are not enough, but the decision should be made with a doctor or midwife rather than by buying a pack yourself. Tell any prescriber or pharmacist that you are pregnant, think you might be, or are breastfeeding, before anything is supplied. Small amounts pass into breast milk. Whether that is acceptable depends on the dose, the reason for treatment and the baby, which is a conversation for your GP, your maternity service or your public health nurse. Because it needs an individual assessment, and because pregnancy changes what is appropriate, our questionnaire is not the right route for starting acid treatment in pregnancy. Speak to the service that is already looking after you.
Where to find the patient information leaflet
Every medicine authorised in Ireland has a patient information leaflet, and the leaflet inside your own pack is the version that applies to you. The Health Products Regulatory Authority (HPRA) keeps a public database of medicines authorised here, where you can look up the leaflet and the summary of product characteristics for the exact strength and manufacturer you have been given. For centrally authorised medicines the European Medicines Agency publishes the same documents. Read the leaflet before the first dose and again if the pack you collect looks different from the last one, because generic versions can differ in their inactive ingredients even when the active substance and the strength are identical. If anything in the leaflet does not match what you were told, ask your pharmacist before taking the medicine. A leaflet is written for the whole patient population, so it lists effects that are uncommon; it is not a prediction of what will happen to you.
Is omeprazole prescription-only in Ireland?
Not entirely. Lower-strength packs for short-term reflux symptoms in adults are supplied by pharmacies without a prescription, so ask at the counter if that is all you need. Higher strengths, longer courses, ulcer treatment and use in children are prescription-only.
How long does omeprazole take to work?
The effect builds over the first days rather than arriving with the first dose, because the medicine switches off acid pumps as they are produced. Judge it after a few days. For instant relief after a meal an antacid works differently and faster; ask your pharmacist.
What are the common side effects of omeprazole?
Headache, abdominal pain, nausea, constipation, diarrhoea and wind are reported most often. Long-term use has been linked with low magnesium, reduced vitamin B12 absorption and a higher risk of gut infections, which is why long-term treatment should be reviewed by a doctor.
Can I drink alcohol while taking omeprazole?
There is no direct interaction, but alcohol increases acid production and relaxes the valve at the top of the stomach, so it tends to provoke the reflux you are treating. Late meals, coffee and smoking do the same.
How do I get a repeat prescription for omeprazole?
If a doctor has already prescribed it as ongoing treatment, fill in our medical questionnaire; a doctor reviews it and, where continuation is appropriate, issues a cross-border prescription as a PDF by e-mail. For occasional heartburn a pharmacy pack is enough and no consultation is needed.