Proton-pump inhibitors are a group of drug

Medication

A pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...

s whose main action is a pronounced and long-lasting reduction of gastric acid

Gastric acid

Gastric acid is a digestive fluid, formed in the stomach. It has a pH of 1 to 2 and is composed of hydrochloric acid , and large quantities of potassium chloride and sodium chloride...

 production. They are the most potent inhibitors of acid secretion available today. The group followed and has largely superseded another group of pharmaceuticals

Pharmacology

Pharmacology is the branch of medicine and biology concerned with the study of drug action. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function...

 with similar effects, but different mode-of-action, called H₂-receptor antagonists

H2-receptor antagonist

The H2 receptor antagonists are a class of drugs used to block the action of histamine on parietal cells in the stomach, decreasing the production of acid by these cells. H2 antagonists are used in the treatment of dyspepsia, although they have been surpassed in popularity by the more effective ...

. These drugs are among the most widely-selling drugs in the world and are generally considered effective.