Losec are omeprezole tablets formulated to provide longlasting relief for the uncomfotable sensations of heartburn and acid reflux. Available in 10mg and 20mg tablets, Losec treats heartburn at its source. Unlike antacids which simply provide symptomatic relief, Losec works by proton pump inhibitors (PPIs) which switch off tiny acid-producing pumps in the stomach. With less acid being produces in the stomach, the less likely that acid will rise into esophagus and irritate sensitive tissue.