Why not ask your GP why he prescribed Omeprazole? Did you complain of stomach upset, gastric reflux or similar? It is a drug that protects(heals lesions in the stomach (often caused by drugs that irriitate the stomach lining ) Thish could lead to ulcers and bleeding .. It is generally given for a certain period, typically 2 -3 months.. it is not without its serious side effects, especially with long term use. It does not stop other drugs from working as far as I know, take it with food and a glass of water, see leaflet.