Thank you for the query. I would like to know your gender and the comorbidities you have (like hypertension, diabetes, bronchial asthma etc.) Omeprazole is a proton pump inhibitor, given to reduce the acid content of the stomach. It is used for various conditions like acid-peptic disorders, gastro-esophageal reflux disease and as a part of H.pylori kit. It is one of the safer drugs, but side effects like abdominal pain, diarrhea, nausea, cough and dizziness may occur in some patients. Because it produces achlorhydria (reduced acid in stomach), clostridium difficile infection may occur on prolonged use. Amoxycillin is a beta lactam antibiotic. Common side effects are rashes, abdominal pain, nausea, vomiting and sometimes on prolonged use antibiotic associated colitis. If you are allergic to penicillin group of drugs, it is advisable to not use it. Clarithromycin is an antibiotic and common side effects are again diarrhea, nausea, abdominal pain and vomiting. It may sometimes cause jaundice in some patients (though rare). Sometimes an ECG is preferred before starting this drug (I am sure your physician has already done that). Propranolol is a non selective beta blocker and it may cause worsening of bronchial asthma/COPD, slow heart rate (leading to dizziness and weakness) and deranged sugar and lipid profile (in some patients). Though you haven t mentioned, the combination of Omeprazole, Amoxicillin and Clarithromycin is usually given as part of Helicobacter pylori treatment regimen. If so, then all these three drugs, will not be used for a very long time, hence the long term side effects should not occur. Hope this helps you out.