A single 15mg capsule of lanzoprazole before breakfast every morning sorts me out for the whole day, including a glass or two of neat malt twelve hours later when required. No heartburn any more, ever. But we're all different and I'm no doctor. Lanzoprazole is a proton pump inhibitor, which means, in simple lingo, that it reduces the amount of acid released into your stomach by the oxyntic cells in the glands in your stomach lining. Your stomach has chemical mechanisms to buffer the acidity of the stomach, but if the acidity is a bit too high and your cardiac sphincter allows some of the fluids to leak back into your oesopagus at its bottom end you get heartburn. You need acid in your stomach to facilitate the breakdown of proteins in food and to kill any nasty bugs in your food. Antacids such as Setlers and Rennies simply neutralise somewhat the acid already present in the stomach. You shouldn't take them with lanzoprazole. If I forget to take the capsule, I'm in trouble by teatime. 15mg once a day is the lowest possible dose of lanzoprazole. You can be prescribed much more than that.