What Is Omeprazole? Everything You Need To Know
Omeprazole is the representative substance in the group of medicines called proton pump inhibitors. These are used for stomach problems such as acidity and gastritis, among others.
We will explain the following aspects that refer to omeprazole:
- The mechanism of action
- Pharmacokinetics
- Metabolism
- Undesirable side effects
- Interactions
- Indications
How omeprazole works
The stomach has an acidic pH value. This is due to HCl produced by parietal cells found in the gastric mucosa.
In fact, the acidic pH of the stomach is crucial for the digestion of food in order to:
- Break down proteins properly.
- Activate the pepsin to peptide so that it can produce proteolysis, or the rupture of the peptide bonds of the proteins.
- Prevent bacterial infections since the bacteria usually do not survive the acidity.
In addition, an excess secretion of stomach acid can cause damage to the lining of the gastrointestinal tract. This mainly produces gastric and duodenal ulcers.
Phases of acid secretion
The secretion of stomach acid takes place in different steps:
- Segregation of the ions H + and Cl- separately in parietal cells
- Their combination to form HCl in canaliculi
- Segregation of acid also from the canaliculus to feed the stomach
Proton pump inhibitors, such as omeprazole, act in the last step of acid production, irreversibly inhibiting ATPH + / K-, a pH-dependent binding with a maximum pH <6. This inhibition occurs through the formation of the covalent bond SS between sulfamide and a cysteine residue available to proton pumps. This connects the residues Cys-813 and Ces-892.
Omeprazole, similar to other proton pump inhibitors, is administered in its neutral form, which is inactive. Moreover, in its neutral form it is lipophilic . This means that it is insoluble in water and is able to cross the cellular membrane easily without any problems.
Since these cells have an acidic pH, they transform the omeprazole from its neutral form to its active proton form. This enables it to complete the mechanism of action and irreversibly bind it to the proton pump and block its action.
- It is labile in acid so that the oral preparations are provided with an enteric coating
- The binding of the plasma proteins increases. More than 95%, which increases its ability to interact with other medicines, as there may be a change in dosage
- Also, it is usually completely absorbed by the small intestine within 3-6 hours
- The oral bioavailability is approx. 35%, and can increase up to 60% with repeated administration once daily
- Its volume of distribution varies from 0.3 l / Kg
Metabolism
Omeprazole suffers from hepatic metabolism through the CYP 45o system. So most of our metabolism depends on the specific isoenzyme CYP2C19.
Furthermore, the majority of the doses administered orally excrete metabolites through the urine and the remainder through feces excreted mainly from bile secretion.
Undesirable side effects
You must keep in mind that omeprozal can present a number of unwanted side effects, but not so many due to the selectivity of the effect, which must be remembered if this drug is used. Among them are:
- Prolonged treatment can cause severe hypomagnesaemia
- Increases the risk of breaking bones
- Skin changes such as itching and rash
- Gastrointestinal changes such as diarrhea, constipation, abdominal pain, nausea or vomiting
- Peripheral neuropathy
- Hypersensitivity
- Hemolytic anemia
- Reduction in the absorption of vitamin B12, so that it may increase the risk of suffering from megaloblastic anemia
- Danger of subacute cutaneous lupus erythematosus (lupus)
- Increase in the levels of chromogranin A, the protein that has also been shown to be high in certain types of cancer
Interactions
Omeprazole interacts with enough drugs which, when co-administered, reduce or increase the effect.
It can reduce the action of:
- Clopidrogerel
- Antifungals
- Phenytoin
- Mycophenolic acid
- Second
It can increase the action of:
- Methotrexate
- Amphetamine
- Benzodiazepines
- Carvedilol
- Citalopram
- Escitalopram
- Cyclosporine
- Warfarin
- Second
Ultimately, it can also interact with many medications. So if you are taking omeprazole with another medication, consult your doctor to avoid complications.
Indications
Used for:
- Ulcer
- Duodenal ulcer
- Oesophagitis caused by reflux (acid regurgitation)
- Zollinger-Ellison syndrome
- Gastritis
- Functional dyspepsia
