Stock Photo: OMEPRAZOLE. Capsules of omeprazole gastrorésistantes dosed at 20 mg generic drug. Omeprazole is a proton pump inhibitor, that notably regulates the gastric acidity. By this action, the omeprazole reduces gastric secretions gastric acid inhibitor which avoids the apparition of peptic ulcers Anti_ulcer drug, and reduces gastro_esophageal reflux Antireflux drug.