Pantobex Drug Interactions

Pantoprazole gastro-resistant tablet may reduce or increase the absorption of drugs whose bioavailability is pH-dependent (e.g. ketoconazole).
HIV medications (atazanavir): It has been shown that co-administration of atazanavir 300 mg/ritonavir 100 mg with omeprazole (40 mg once daily) or atazanavir 400 mg with lansoprazole (60 mg single dose) to healthy volunteers resulted in a substantial reduction in the bioavailability of atazanavir. The absorption of atazanavir is pH-dependent. Therefore PPI's, including pantoprazole must not be co-administered with atazanavir (see Contraindications).
Coumarin anticoagulants (phenprocoumon or warfarin): Although no interaction during concomitant administration of phenprocoumon or warfarin has been observed in clinical pharmacokinetic studies, a few isolated cases of changes in International Normalised Ratio (INR) have been reported during concomitant treatment in the post-marketing period.
Therefore, in patients treated with coumarin anticoagulants (e.g. phenprocoumon or warfarin), monitoring of prothrombin time/INR is recommended after initiation, termination or during irregular use of pantoprazole.
Methotrexate: Concomitant use of high dose methotrexate (e.g. 300 mg) and proton-pump inhibitors has been reported to increase methotrexate levels in some patients. Therefore in settings where high-dose methotrexate is used, for example cancer and psoriasis, a temporary withdrawal of pantoprazole may need to be considered.
Case reports, published, population pharmacokinetic studies and retrospective analyses suggest that concomitant administration of PPls and methotrexate (primarily at high dose) may elevate andprolong serum levels of methotrexate and/or its metabolite hydroxymethotrexate. However, no formal drug Interaction studies of methotrexate with PPls have been conducted (see Precautions).
Other Interactions studies: Pantoprazole is metabolized in the liver via the cytochrome P450 enzyme system. The main metabolic pathway is demethylation by CYP2C19 and other metabolic pathways include oxidation by CYP3A4.
An interaction of pantoprazole with other drugs or compounds which are metabolized using the same enzyme system cannot be ruled out. However, in targeted studies involving a range of such drugs and substances, no clinically significant interactions were observed; studies have been carried out on carbamazepine, caffeine, diazepam, diclofenac, digoxin, ethanol, glibenclamide, metoprolol, naproxen, nifedipine, phenytoin, piroxicam, theophylline and all oral contraceptive.
Interaction studies with drugs also metabolized with these pathways, like carbamazepine, diazepam, glibenclamide, nifedipine and an oral contraceptive containing levonorgestrel and ethinyl oestradiol did not reveal clinically significant interactions.
Results from a range of interaction studies demonstrate that pantoprazole does not effect the metabolism of active substances metabolized by CYP1A2 (such as caffeine, theophylline), CYP2C9 (such as piroxicam, diclofenac, naproxen). CYP2D6(such asmetoprolol). CYP2E1 (such as ethanol), or does not interfere with p-glycoprotein relatedabsorption of digoxin.
There were also no interactions with concomitantly administered antacids.
Interaction studies have also been performed by concomitantly administering pantoprazole with the respective antibiotics (clarithromycin, metronidazole, amoxycillin). No clinically relevant interactions were found.