Rabeprazole is metabolized by the CYP-450 liver enzyme system - elements such as CYP2C19, and CYP3A4. The substance does not have drug-relevant or pharmacokinetic interactions with phenytoin, diazepam, warfarin, or theophylline (all of which are metabolized with the CYP-450 system).
Interactions provoked by oppression of the processes of gastric acid secretion.
Rabeprazole sodium contributes to a prolonged and powerful decrease in the production of hydrochloric acid. Because of this, the substance can interact with drugs, the absorption of which depends on the level of gastric pH. When a combination of Geerdin with itraconazole or ketoconazole, the plasma values of the latter may decrease, and when combined with digoxin, an increase in the latter is observed. Therefore, those who combine the above drugs with rabeprazole require constant monitoring during treatment - in order to adjust the dosage in time.
The combination of atazanavir (300 mg) / ritonavir (100 mg) with omeprazole (single 40 mg per day) or atazanavir (400 mg dose) with lansoprazole (a single 60 mg dose per day) significantly reduces the level of AUC atazanavir. The absorption of this component depends on the pH value. Similar results can be expected with other proton pump inhibitor drugs. Therefore, they (including rabeprazole) are not allowed to be used together with atazanavir.
When combined with food that contains a small amount of fat, the absorption of rabeprazole does not change. In the case of use with fatty dishes, absorption can be slowed down for 4+ hours, but its degree, as well as the peak concentration of the substance, do not change.
In vitro studies revealed that rabeprazole slows the metabolism of the substance cyclosporin. The inhibition rate in this case is similar to the level of inhibition by omeprazole.
Medicines that are forbidden to combine with the component rabeprazole: sulphate atazanavir - because its medicinal effect may be weakened. The antisecretory properties of rabeprazole increase the gastric acidity index and decrease the solubility of atazanavir sulfate, as a result of which its plasma level also decreases.
Medications prescribed with caution:
- digoxin and methyldigoxin - their indices inside the blood can increase. The anti-secretory effect of Geerdin helps to increase the value of gastric pH, which is why the absorption of the above substances is accelerated;
- gefitinib and itraconazole - it is possible to reduce the indices of these components inside the blood. An increased level of pH in the stomach results in the fact that the absorption of these elements slows down;
- Aluminum- and magnesium-containing antacid drugs - with the combination of rabeprazole and antacid agents, a decrease in the values of this substance is observed.