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. Ease heartburn without drugs: Many people who have heartburn don’t need drugs at all. They can feel better by making changes in their diet and lifestyle. Acid reflux / indigestion. Losec (Omeprazole) and Zantac (Ranitidine) for acid reflux / indigestion and heartburn. Medicine on prescription from UK pharmacy. Doctors give trusted answers on uses, effects, side-effects, and cautions: Dr. Chiu on take omeprazole at night: Prilosec works best when taken before a meal and not when fasting. Taken with or without food. Does not need acid in the stomach to get absorbed. Good choice if you take medications that reduce stomach acid. *** myDr. myDr provides comprehensive Australian health and medical information, images and tools covering symptoms, diseases, tests, medicines and treatments, and nutrition and fitness. Doctors give trusted answers on uses, effects, side-effects, and cautions: Dr. Fowler on can you take zantac and omeprazole together: Usually it is one or the other. However you can use both if you have severe gerd or peptic ulcer disease, because of their different modes of action. If bleeding, sucralfate is added. This handout has been adapted by RxFiles, with permission, from The Vermont Academic Detailing Program () with consideration for Deprescribing Guidelines for the When proton pump inhibitor (PPI) drugs were first introduced decades ago, the perception was that these drugs had hardly any side effects. Both doctors and their patients were convinced that omeprazole (Prilosec), the first PPI, was both very powerful and extremely safe. Hello, Prilosec contains omeprazole and both pantoprazole and omeprazole belong to the same group. If pantoprazole is not helping you, you can take ranitidine or gelusil after consulting your gastroenterologist.