If you've been taking omeprazole for more than 2 weeks, you're body has adapted by creating more acid secreting cells. This means that once you stop the omeprazole you can have what's called rebound heartburn. Normally the omeprazole blocks these acid secreting cells. The longer you take it, the more your body wants to get back to its regular state so it produces more acid secreting cells (proton pumps). The best way to get off of omeprazole is to first speak to your doctor and then follow a very slow weaning regimen. One of the most popular ways is to replace one dose per week of omeprazole with famotidine. Do this every week or every two weeks until you are only taking the famotidine. From there you can slowly wean off the famotidine. It's never a good idea to completely stop a medication without first speaking to your doctor or pharmacist as some medications can have dangerous effects from sudden discontinuation.