ML-Gacid Drug Interactions

Omeprazole can prolong the elimination of medicines which are metabolised by oxidation in the liver, e .g. warfarin, diazepam and phenytoin.
Patients receiving warfarin or phenytoin concomitant with omeprazole, should be monitored closely as a reduction in dosages of warfarin or phenytoin may be required.
It was however shown in patients on concurrent omeprazole treatment at a daily dosage of 20 mg and continuous phenytoin treatment, that the simultaneous use of these two medications did not influence the blood concentration of phenytoin. Concomitant treatment with omeprazole 20 mg daily also did not alter coagulation time in patients on long-term treatment.
There is a possibility of interactions with medicines metabolised via the cytochrome P450 enzyme system, although no interactions with propranolol, metoprolol, theophylline, lignocaine, quinidine and amoxicillin have been recorded.
No interaction with food or the concurrent administration of antacid medications has been found.
The plasma concentrations of both omeprazole and clarithromycin may be increased during concomitant treatment with these medicines.
An increase of approximately 10% in the bioavailability of digoxin were recorded in healthy volunteers due to the increase in intragastric pH when omeprazole and digoxin are administered concurrently.