[Protonic pump inhibitors in kidney transplant patients: efficacy and safety]

Kidney transplant patients show a significantly elevated incidence of gastrointestinal disorders. Protonic pump inhibitors (PPI) are considered to be the correct therapy in the treatment of peptic ulcers, as they have proven to be safe and efficient. The metabolization of the PPIs mainly occurs on a hepatic level; therefore, there is no need to change the therapy accordingly, as there is with the inhibitors of the histamine receptors (anti-H2). The PPIs currently available are omeprazole, pantoprazole, lansoprazole, esomeprazole, rabeprazole which present different pharmacokinetic characteristics and different metabolic routes which are responsible both for differences in terms of efficacy between the different molecules, and for the possible side-effects they may have. All the PPIs, apart from rabeprazole, are metabolized through an oxidization and sulphurization processes which involves the enzymatic system of the P450 cytochrome. The rabeprazole metabolism is different from the other molecules of the same category in that it only moderately involves the CYP450 (CYP3A4 and CYP2C19) from the moment its metabolization begins through nonenzymatic routes and 80% is involved in a thioether non enzymatic reduction mechanism. Consequently, rabeprazole represents: a) a potentially low pharmacological interaction with immunosuppressive drugs; b) a pharmacokinetic aspect much less subject to interindividual differences between one patient and another, due to genetically determined polymorphisms of the CYP2C19 and of the CYP3A4. Moreover, rabeprazole may be administered safely in standard doses with no need to change the dosage of the other pharmaceutical drugs taken simultaneously in nephropathic patients, patients undergoing dialysis and transplanted patients.