Changes in absorption should be observed when drugs whose absorption is pH-dependent eg, ketoconazole, are taken concomitantly.
It has been shown that co-administration of atazanavir 300mg/ritonavir 100mg with omeprazole (40mg once daily) or atazanavir 400mg with lansoprazole (60mg single dose) to healthy volunteers resulted in a substantial reduction in the bioavailability of atazanavir. The absorption of atazanavir is pH dependent. Therefore PPIs, including Pantoprazole, should not be co-administered with atazanavir.
Please note that this information also applies to drugs which patient might have used recently.
Pantoprazole sodium is metabolized in the liver via the cytochrome P-450 enzyme system. An interaction of Pantoprazole with other drugs or compounds which are metabolized using the same enzyme system cannot be excluded. However, no clinically significant interactions were observed in targeted studies with drugs or compounds such as carbamazepine, caffeine, diazepam, diclofenac, digoxin, ethanol, glibenclamide, metoprolol, naproxen, nifedipine, piroxicam, theophylline, phenytoin and an oral contraceptive.
Although no interaction during concomitant administration of phenprocoumon or warfarin has been observed, a few isolated cases of changes in INR have been reported. Therefore, in patients being treated with coumarin anticoagulants, monitoring of prothrombin time/INR is recommended after initiation, termination or during irregular use of pantoprazole.
There were also no interactions with concomitantly administered antacids.