How omeprazole works
Omeprazole is a drug from the group of proton pump inhibitors (PPI) and – like other representatives of this group of active ingredients – can increase the pH value of the stomach (i.e. make the stomach less acidic):
After being taken by mouth (orally), omeprazole is absorbed from the small intestine into the blood. Via the bloodstream, it reaches the gastric mucosal cells. These are responsible for the production of gastric acid (mainly consisting of hydrochloric acid).
In the membrane of these cells, omeprazole blocks a transport protein called the proton pump. This protein “pumps” protons into the inside of the stomach as a component of hydrochloric acid. The end result is that omeprazole irreversibly inhibits acid production, making the environment in the stomach less acidic. The extent to which omeprazole blocks stomach acid production depends on its dosage.
Omeprazole is a “prodrug”.
As a so-called “prodrug,” omeprazole is not converted into its active form until it reaches its site of action. Because the active ingredient would decompose in the acidic environment of the stomach, tablets and capsules containing omeprazole are coated with an enteric coating. With the exception of some preparations, the tablets and capsules must therefore not be cut, crushed or opened before taking them.
When is omeprazole used?
Omeprazole is used for inflammation and ulcers of the esophagus, stomach, and small intestine – both to treat and prevent recurrence. Main indications are:
- gastric and duodenal ulcer (ulcus ventriculi, ulcus duodeni)
- inflammation of the esophagus caused by reflux of gastric juice (reflux esophagitis)
- Zollinger-Ellison syndrome (tumor disease with increased gastric acid production)
- Killing of the bacterium Helicobacter pylori (combination therapy with antibiotics)
The “stomach germ” Helicobacter pylori can cause gastritis, which can subsequently cause a stomach ulcer.
How omeprazole is used
In the treatment of acute diseases, omeprazole is taken orally as an enteric-coated capsule or tablet, as it is supposed to pass through the stomach for its effect and only be dissolved and absorbed in the small intestine. It is recommended to take it in the morning 30 minutes before breakfast on an empty stomach.
Anyone who wants to use the drug on their own (self-medication) may take a maximum of 20 milligrams of omeprazole per day for a maximum of two weeks. If the symptoms have not improved after this time, you should go to the doctor.
For the treatment of Helicobacter pylori infection, omeprazole is administered together with several antibiotics (including clarithromycin, amoxicillin, metronidazole).
Omeprazole solutions for infusion are available for the treatment of acute bleeding peptic ulcers.
What are the side effects of omeprazole?
Omeprazole is usually very well tolerated. One in ten to one in a hundred patients develops gastrointestinal symptoms (such as diarrhea, constipation, bloating) as side effects of treatment – probably because bacterial populations in the intestines are no longer as regulated by stomach acid under the influence of omeprazole.
Similarly common to gastrointestinal complaints are headaches, dizziness, fatigue, and sleep disturbances as side effects.
In addition, the reduced stomach acid production makes digestion more difficult. The reason: many digestive enzymes can only work optimally at the low pH of gastric acid. This is especially true for enzymes that are responsible for breaking down proteins.
When should omeprazole not be taken?
Interactions
Omeprazole is broken down in the body by enzymes (mainly CYP2C19) that are also responsible for the breakdown of other drugs. Taking omeprazole at the same time as such drugs may therefore lead to drug interactions.
In addition, omeprazole may affect the breakdown of the following drugs:
- diazepam (tranquilizers)
- Warfarin and phenprocoumon (anticoagulants)
- Phenytoin (antiepileptic drug)
- Drugs with pH-dependent absorption (e.g., HIV drugs such as atazanavir and nelfinavir)
Age restriction
Omeprazole is approved for use from 1 year of age and a body weight of at least 10 kilograms.
Pregnancy and lactation
There is no evidence of fetal malformations when taken during pregnancy. Omeprazole is therefore one of the drugs of choice when pregnant women are to be treated with medication for reflux esophagitis or for the prevention of gastritis.
The use of omeprazole during breastfeeding has been less well studied. However, if a proton pump inhibitor is needed, omeprazole can be used during breastfeeding.
How to obtain medicines containing omeprazole
Omeprazole can be purchased over-the-counter at pharmacies in Germany, Austria, and Switzerland in packs of up to 14 (corresponding to a daily dose of up to two weeks), each containing a maximum of 20 milligrams.
In higher dosages and package sizes, as well as for intravenous administration, omeprazole requires a prescription.