MECHANISM OF ACTION OF PANTOPRAZOLE: Pantoprazole, a new proton-pump inhibitor, is a drug which demonstrates precision from the molecular level to the patient. Like other H+, K(+)-ATPase inhibitors it has in-built selectivity because it accumulates in the acidic compartment of the parietal cell and has to be acid-activated before it acts on the proton pump.
Stability of pantoprazole: Pantoprazole is chemically more stable than the other proton-pump inhibitors, particularly at near neutral pH, and therefore is unlikely to interact with thiol-containing proteins outside the parietal cell. This acid stability may also account for its highly selective binding to the two cysteine groups located in the proton-pumping pathway of the enzyme.
Conclusions: Pantoprazole is characterized by a degree of pharmacokinetic precision not associated with the other drugs. It shows linear kinetics after oral and intravenous administration. It has a high and constant bioavailability (approximately 77%) which does not change on multiple dosing, so that maximum blood levels are achieved after the first dose. Bioavailability is not altered by concomitant antacid administration, and dose adjustment is not required in elderly patients or those with chronic renal impairment. Extensive studies in man have found no interaction with other drugs. Because of this pharmacokinetic profile, a standard doses of 40 mg is optimal and can be used with confidence in subgroups of patients to give a predictable therapeutic effect.