What Is Omeprazole? Everything You Need To Know
Omeprazole is the representative drug of the group of drugs under the name of proton pump inhibitors. These are used, among other things, for stomach problems such as heartburn and gastritis.
We are going to explain the following aspects related to omeprazole:
- Mechanism of action
- Pharmacokinetics
- Metabolism
- Effects
- Interactions
- Indication
How does omeprazole work?
The stomach has an acidic pH value. This is due to the hydrogen chloride in the stomach mucus.
After all, the acidity of your stomach acid is essential for the digestion of food. This is mainly important for these two reasons:
- To break down proteins correctly.
- To prevent bacterial infections, as the bacteria usually do not survive in the stomach acid.
But too much stomach acid can cause damage to the mucous membrane. This causes stomach ulcers and also damage to the duodenum.
Phases of acid secretion
The secretion of stomach acid takes place in several steps:
- Secretion of the ions H+ and Cl- separately in the parietal cells.
- Combining those ions into HCl in the cells.
- Secretion of acid from the cells to the stomach.
The proton pump inhibitors, such as omeprazole, act in the last step of acid production, where the ATPH+/K- becomes irreversible. This is in fact a pH-dependent substance with a maximum pH of 6. This inhibition then takes place through the formation of the covalent substance SS between sulfamide and a cysteine residue that is accessible to the proton pumps. Finally, this links the residues Cys-813 and Ces-892 to each other.
Omeprazole, as with other proton pump inhibitors, is administered in its neutral form, which is inactive. In addition, in its neutral form, it is lipophilic. This means that it is insoluble in water and is also able to cross the cellular membrane without any problem.
Since these cells have an acidic pH, they transform the omeprazole from its neutral form to its active proton form. This then enables it to complete the mechanism of action and bind irreversibly to the proton pump, thus blocking its action.
- It is low in acid, so that the oral preparations are provided with an intestinal cover.
- The binding of the plasmatic proteins then increases. Over 95%, which increases its ability to interact with other drugs as it may experience a shift in dosage.
- In addition, it is usually completely absorbed by the small intestine between 3 and 6 hours.
- The oral bioavailability is about 35% but can be as high as 60% with repeated once daily dosing.
- The distribution volume has a spectrum of 0.3 L/Kg.
Metabolism
However, omeprazole mediates hepatic metabolism through the CYP 45o system. So most of our metabolism depends on the specific isoenzyme CYP2C19.
In addition, the majority of doses administered orally excrete inactive metabolites in the urine and the remainder in feces, mainly via biliary secretion.
Effects
You should keep in mind that omeprazole can have some side effects, although not many due to the selectivity in the action of the drug. These include:
- Long-term treatments can cause severe blood poisoning.
- Increased risk of broken bones.
- Skin changes such as itching and rash.
- Gastrointestinal changes such as diarrhoea, constipation, abdominal pain, nausea or vomiting.
- Peripheral neuropathy
- Hypersensitivity
- Hemolytic Anemia
- Reduction of vitamin B12 absorption, which may increase the risk of megaloblastic anemia.
- Risk of subacute cutaneous lupus erythematosus (lupus).
- Increase in the level of chromogranin A, the protein that is also found in high levels in certain types of cancer.
Interactions
Omeprazole responds to sufficient drugs which, when administered concomitantly, reduce or increase their effect.
It can reduce the effect of:
- Clopidrogrel
- Antifungals
- phenytoin
- mycophenolic acid
- Others
It can increase the effect of:
- Methotrexate
- Amphetamines
- Benzodiazepines
- carvedilol
- Citalopram
- Escitalopram
- Cyclosporine
- warfarin
- Others
Ultimately, it can also interact with numerous drugs. So if you are taking omeprazole with any other medication, consult your doctor to avoid complications.
Indications
Used for:
- stomach ulcers
- intestinal ulcers
- Esophagitis caused by reflux
- Ollinger-Ellison syndrome
- Gastritis
- Functional Dyspepsia
Always use common sense when taking medication, or consult your doctor!
