Omeprazole is used to treat certain stomach and esophagus problems (such as acid reflux, ulcers). It works by decreasing the amount of acid your stomach makes. It relieves symptoms such as heartburn, difficulty swallowing, and persistent cough. This medication helps heal acid damage to the stomach and esophagus, helps prevent ulcers, and may help prevent cancer of the esophagus. Omeprazole belongs to a class of drugs known as proton pump inhibitors (PPIs).
if you are taking only one tablet I found that the best relief was first thing in the morning. If twice a day then I always take it about an hour before going to bed this stops the acid from waking me in the night - it might not work for everyone but it does for me.
I have been on Omeprazole for some time now, due to having a hiatus hernia with acid reflux and GERD. I found it was great when I was in a lot of pain, helped to control my symptoms. I have been on a maintenance dose of 20mg a day and have only had to increase it once in the last few years to 40mg when symptoms flared. I do find though that the brands the chemists dish out from time to time are not as effective. The ones I get given now by my chemist are named prenome and I don't think they are as good as the original brand I was on.