I have gastroparesis for 7 months. I was prescribed omeprazole, 25 mgs, 2 x day. My doctor then increased this dosage to 4x daily. I still have heartburn, chest pain regardless. I ve been reading that Omeprazole can cause gastroparesis. Previously, for 2 years, I ve been taking Vicodin 4x daily for fibro pain. Stopped the Vicodin in April, with no improvement in gastric emptying.