Proton-pump inhibitors (omeprazol, lansoprazol, esomeprazol, pantoprazol and rabeprazol) are used to eradicate Helicobacter pylori and in the brief and prolonged therapy for gastro-oesophageal reflux  and ulcers, but currently they are prescribed along with many other therapies to protect the stomach, even when there is no need.

The damage resulting from prolonged used of these medicines are important, as they interfere with the digestion and inhibit the absorption of calcium and magnesium, favoring osteoporosis.  This is the result of a retrospective study conducted on a group of patients, utilizing the data taken from the Population Health Research Data Repository, which contains information on the health of the majority of residents in Canada and Manitoba.  The mechanism through which the risk of fractures is increased is not completely clear, although it is obvious that, as calcium carbonate is the main source of calcium introduced through the diet, this cannot be absorbed as it is insoluble with high pH values.   Additionally,  it appears that pump inhibitors can also inhibit the H+/ATPasi pump present on the cellular membrane of osteoclasts.

Another study connects the long-term use of pump inhibitors with the growth of some tumors, especially of the digestive system (Jianu CS et al, Aliment Pharmacol Ther. 2012 Oct;36(7):644-9. doi: 10.1111/apt.12012. Epub 2012 Aug 5).

Not to mention that the inhibition of gastric acidity blocks digestive enzymes,  allowing many substances to enter the intestine undigested, causing chronic inflammation from food that in the long-term could result in serious allergies.

Therapy with these medicines also causes a significant increase in intestinal infections, especially Salmonella e Campylobacter, probably favored by the inhibition of gastric acidity.  There is also an increase in the malabsorption of iron in anemic patients, and in atrophic gastritis it reduces the absorption of vitamin B 12.