<p>Lansoprazole appears to be a selective inhibitor of the cytochrome P-450 monooxygenase system; there may be an effect on hepatic clearance, but there have been no reports to date of clinically relevant interactions. There is some uncertainty over the effect of Lansoprazole on the oral combined contraceptive pill. Further assessment is currently underway. Physiological changes similar to those found with Omeprazole are likely to take place because of the reduction in gastric acid, which is likely to influence the bacterial colonization of the stomach and duodenum and also vitamin B12 absorption.</p>