Omeprazole is the forefather of the class of proton pump inhibitors and is one of the most widely used drugs in the treatment of gastritis. Omeprazole is marketed under the name of several registered specialties: Antra ®, Omeprazen ®, Omolin ® Nansen ® and Protec ®. On the market, it can also be found as a generic drug under the name of Omeprazole.
Omeprazole is a pro-drug that acts on the parietal cells of the stomach, where it is protonated and converted into its active form, which then binds to the proton pump, inhibiting it.
Posology and method of use
Before starting the treatment of gastritis or duodenal ulcer with omeprazole it is necessary to exclude the possibility of a malignant ulcer through various diagnostic means because treatment with omeprazole can delay and mask the onset of symptoms, making treatment more difficult and the healing of the same. If we administer 20 to 30 mg of omeprazole / day we have complete inhibition of acid secretion in the stomach for 6 hours and a reduction of secretion by 90% for more than 24 hours after intake. Instead if we want to block the secretion completely for 24 hours the dose to be taken is 40 mg / day.>In the treatment of gastritis the dose used is 20 mg of omeprazole in a single morning administration, fasting, to be repeated for 4 weeks; the most severe cases may require longer times (6 to 8 weeks) to achieve complete healing of the ulcer. In the presence of a particularly severe ulcer, the dose should be doubled (40 mg) and administered for 8 weeks. In case of intravenous intake in adults 40 mg / day are administered until oral intake becomes possible.
When treating duodenal ulcer, 20 mg / day of omeoprazole are used, to be taken in a single dose in the morning and on an empty stomach; generally, in most patients relief from symptoms is achieved within 48 hours of first use of the drug. The duration of treatment is based on the complete healing time of the ulcer, which is generally 2-4 weeks. In severe cases the dose is increased to 40 mg / day and the healing usually occurs after 4 weeks. For prophylaxis of duodenal ulcer recurrence the maintenance dose is 10 mg / day.
In the treatment for the eradication of Helicobacter pylori, 20 mg / day of omeoprazole is used in combination with two antibiotics for seven days, or 40 mg / day is used for two weeks, in combination with only one antibiotic. The most widely used antibiotics in triple therapy are: clarithromycin, amoxicillin, tetracycline and metronidazole. Depending on the need, treatment with triple therapy can be repeated a second time.
In gastroesophageal reflux disease the attack dose is 20 mg / day for 4-8 weeks, but in more severe cases it can be doubled (40 mg / day). The maintenance dose for relapse prophylaxis is 10-20 mg / day.
10 mg / day of omeprazole are used in the treatment of this disease in children over 2 years of age and body weight of 20 kg; 20mg / day is used in children older than 2 years and with a body weight over 20 kg.
Contraindications and warnings for use
Omeprazole, like the whole class of proton pump inhibitors, is metabolized by the large CYP450 family; therefore, in cases of joint intake with other drugs that use these same metabolic pathways, attention must be paid to the dosage of both drugs, because there may be variations in the bioavailability of both. For example, in the antiplatelet treatment with Clopidogrel, some studies have shown a decrease in the effect of the drug when it is administered together with omeprazole or other proton pump inhibitors. In these cases it is recommended to replace omeprazole with antihistamines (anti-H2). Another important case is that of Warfarin, whose co-administration with that of omeprazole increases its bioavailability, so it becomes necessary to reduce the dose of warfarin to prevent damage from excess anticoagulant.
Pregnancy and breastfeeding
There is not much information on the use of omeprazole in pregnant women. However, the lack of experience in this regard does not indicate any increase in the risk of congenital malformations or other harmful effects of omeprazole on the fetus or on pregnancy. Animal studies also do not suggest any direct or indirect adverse effect on reproduction. However, it is confirmed that omeprazole is excreted in breast milk, so the prescription should only be made if inevitably necessary and in any case always taking into account the benefit of breastfeeding for the baby and the need for treatment for the mother.
Side and unwanted effects
The most frequent side effects of omeprazole are nausea, vomiting, diarrhea, abdominal pain, constipation, drowsiness, dizziness and headache. The intensity of nausea is a factor that depends on the dose of the drug taken. In a study that considered most proton pump inhibitors, it turned out that the most common side effects of these drugs was diarrhea; however, with the intake of omeprazole there is the advantage that side effects such as nausea, vomiting and headache occur with less intensity than those generated by other PPIs, such as lansoprazole or pantoprazole.
