Proton pump inhibitors are approved in Germany and other countries for certain diseases that can be regulated by reducing stomach acid. Frequent application finds proton pump inhibitors thus with diagnoses such as stomach and intestine ulcers, stomach burn, Refluxkrankheit, Helicobacter Pylori eradications (together with antibiotics) and with a Zollinger Ellison syndrome. They are also frequently prescribed together with so-called NSAIDs (painkillers such as acetylsalicylic acid, ibuprofen, diclofenac), and are intended to act as “stomach protection” in these cases, i.e. to protect against bleeding of the mucous membranes in the stomach.
Mode of action
In healthy people, the stomach acid has a pH of 1-1.5 (fasting) and 2-4 (full stomach), depending on how long ago the last meal was. Gastric acid is an essential component of digestion and the body’s own defenses. Only through it can certain foods, especially proteins, be digested and bacteria be fought off early.
In certain cases, it is possible that stomach acid is produced in greater quantities and that the gastric juice is too acidic overall. The acid also interferes when it enters the esophagus through a sphincter weakness (reflux, symptom: heartburn). In these diagnoses, proton pump inhibitors are used to reduce the acidity of the gastric juice.
Proton pump inhibitors are medicines, which are sold in Germany under the names Omeprazol, Lansoprazol, Pantoprazol, Rabeprazol and the Esomeprazol. Paradoxically, the active ingredients of these drugs must be packaged in an acid-proof capsule to prevent them from being destroyed by the gastric juice. The active ingredient is absorbed only after the tablet has passed through the stomach and is located in the duodenum.
These substances are so-called “prodrugs”, as they are only converted into their active form at their destination, the cells in the stomach. The parietal cell of the stomach contains a transporter that transports hydrogen ions into the stomach in exchange with potassium ions. Inside the stomach, the hydrogen ions are used to form hydrochloric acid with chloride ions, which is the acid of the gastric juice.
This transporter is often called a proton pump. The transporter is also the site of action of the proton pump inhibitor. After the active ingredient has been absorbed in the small intestine and has reached the cells in the stomach via the blood, it irreversibly inhibits this proton pump.
This means that the inhibited transporters do not resume their work, but new proton pumps must be built to transport hydrogen ions into the stomach and produce stomach acid. During the day, however, about one third of the existing proton pumps are newly formed, so the irreversible inhibition cannot cause an absolute, long-lasting acid deficiency. Thus the total acid content in the stomach can be efficiently reduced by proton pump inhibitors.
The approximate pH value of the gastric juice increases under the intake of proton pump inhibitors to about 3-4 in the fasting state. Due to the firm binding to the document cell and a long duration of action of the substance, one tablet a day is sufficient in most cases, although it should be noted that the effect of the medication is usually only felt after one day. It is generally recommended that the drugs be taken about half an hour before a meal.
Depending on the disease, therapy with proton pump inhibitors is recommended for different lengths of time. For example, patients who complain of heartburn are usually free of symptoms within a few days, and can then take the medication initially only in the event of recurring symptoms. The healing process for other diseases may take considerably longer. For example, it is recommended that proton pump inhibitors should be taken for up to 6 weeks when treating a stomach ulcer or esophagitis.
