Due to a decrease in the acidity of gastric juice in the treatment with omeprazole, absorption of other medicines may decrease or increase (LC), the absorption mechanism of which depends on the pH of the gastric juice.
Reduces the absorption of ketoconazole and itraconazole.
Increases absorption of digoxin. Joint use of omeprazole at a dose of 20 mg 1 time per day and digoxin increases the bioavailability of digoxin by about 10%.
It was shown that omeprazole interacts with some antiretroviral AC. The mechanisms and the clinical significance of these interactions are not always known. An increase in pH in the stomach with omeprazole therapy may affect the absorption of antiretroviral drugs. It is also possible to interact at the isoenzyme level CYP2C19. When combined with omeprazole and antiretroviral drugs, such as atazanavir and nelfinavir, against the background of therapy with omepazolom, there is a decrease in their concentration in the serum. In this regard, the joint use of omeprazole with atheretroviral drugs, such as atazanavir and nelfinavir, Not recommended.
With the simultaneous use of omeprazole and saquinavir, an increase in saquinavir concentrations inblood serum.
Omeprazole inhibits CYP2C19 - the main isoenzyme involved in its metabolism. Joint use of omeprazole with other drugs, in the metabolism of which takes part isoenzyme CYP2C19, such as diazepam, phenytoin, warfarin, other antagonists of vitamin K and cilostazol, can lead to a decrease in the metabolism of these drugs.
It is recommended to control the concentration of phenytoin in the plasma with simultaneous application of phenytoin and omeprazole; in some cases, a reduction in the dose of phenytoin may be required. At the same time, patients with long-term phenytoin, the combined use of omeprazole at a dose of 20 mg 1 time per day did not cause a change in the concentration of phenytoin in the blood plasma.
When using omeprazole in patients receiving warfarin or other antagonists of vitamin K, control of the international normalized relationship (INR) is necessary; in some cases it may be necessary to reduce the dose of warfarin or other antagonist of vitamin K. At the same time, in patients taking long-term warfarin, the combined use of omeprazole at a dose of 20 mg 1 time per day did not cause a change in clotting time.
The use of omeprazole in a dose of 40 mg once a day led to an increase in stachia and area under the curve "concentration-time" (AUC) of cystostaxol by 18% and 26%, respectively; for one of the active metabolites of cilostazol, the increase was 29% and 69%, respectively.
Omeprazole does not affect the metabolism of drugs that are metabolized by isoenzyme CYP3A4, such as, ciclosporin, lidocaine, quinidine, variety, erythromycin and budesonide.
With the simultaneous use of omeprazole and tacrolimus, there was an increase in the concentration of tacrolimus in the blood serum.
In the metabolism of omeprazole, isozymes participate CYP2C19 and CYP3A4. The combined use of omeprazole and isozyme inhibitors CYP2C19 and CYP3A4, such as, clarithromycin and voriconazole, can lead to an increase in the concentration of omeprazole in the blood plasma by slowing the metabolism of omeprazole. The combined use of voriconazole and omeprazole led to more than a twofold increase AUC omeprazole, which however did not require correction of the dose of omeprazole.
LS inducing isoenzymes CYP2C19 and CYP3A4, such as, rifampicin and preparations of St. John's wort perfumed, when combined with omeprazole may lead to a decrease in the concentration of omeprazole in the blood plasma due to the acceleration of the metabolism of omeprazole.