Anyone who has purchased omeprazole will have noticed a clear NHS warning advising against using the drug for longer than two weeks due to its possible impact on the body. Omeprazole belongs to a group of medicines known as proton pump inhibitors, or PPIs, and is commonly used across the UK to treat conditions such as heartburn, stomach ulcers, and gastro-oesophageal reflux disease.How Omeprazole Works and How It Is Prescribed?Omeprazole works by reducing the amount of acid produced in the stomach. It comes in several forms, including capsules, tablets, and liquid preparations. While some versions can be bought directly from pharmacies or shops, the medicine is most often prescribed by a GP.Although it is effective at easing symptoms linked to excess stomach acid, health experts caution against long-term use. Taking omeprazole for extended periods has been linked to a higher chance of developing certain side effects, which is why routine, prolonged use is usually discouraged.What NHS Guidance Says About Duration of UseThe NHS clearly advises people who buy omeprazole without a prescription not to take it for more than two weeks. Its guidance states: “Do not take omeprazole for longer than 2 weeks if you bought it without a prescription. See a GP if your symptoms get worse or do not get better.”In cases where symptoms are more severe or ongoing, a GP may recommend continuing the medication for longer under medical supervision. However, anyone worried about the risks of taking omeprazole beyond a fortnight is advised to discuss this with their doctor or another qualified healthcare professional.Possible Side Effects of OmeprazoleLike all medicines, omeprazole can cause side effects, although not everyone will experience them. According to NHS information, some side effects are more likely to appear if the drug is taken continuously for 12 months or longer.Common Side EffectsMilder and more common side effects associated with omeprazole include:ConstipationHeadachesDiarrhoeaFeeling sickExcess windStomach painVomitingMore Serious Risks to Be Aware OfLess common but more serious side effects linked to omeprazole use include weakened bones, which may increase the risk of fractures. In rare cases, people may experience anaphylaxis, a severe allergic reaction that can cause swelling of the tongue or throat, an itchy raised rash, and difficulty breathing.Other reported risks include a form of lupus that can lead to joint pain and skin rashes, as well as low vitamin B12 levels, which may result in tiredness, muscle twitching, and dizziness.When to Seek Medical Help?The NHS also advises calling 111 if you are taking omeprazole and believe you may be experiencing serious side effects. This list does not cover every possible reaction, and individual responses to the drug can vary.For full guidance, patients are encouraged to read the leaflet included with their medication. More detailed information on how to take omeprazole safely, along with a complete breakdown of potential side effects, is available on the NHS website.