Olesja Rissling analyzes the potential interaction of mycophenolic acid (MPA) and pantoprazole. MPA is used as an immunosuppressive drug to prevent acute organ rejections after organ transplantation. Pantoprazole, known to interact with the bioavailability of drugs, is used to prevent upper gastrointestinal disorders. The author performed a clinical pharmacokinetic study in renal transplant patients to evaluate a potential interaction of MPA and pantoprazole. The bioavailability and the maximum concentration of MPA were determined with or without pantoprazole intake. An influence on the immunosuppressive effect was evaluated by measuring the target enzyme activity. Overall, no significant change in the bioavailability or the maximum concentration was found. Similar results were obtained for the target enzyme activity after pantoprazole intake with MPA. The results suggest that the interaction of pantoprazole with MPA does not compromise the immunosuppressive effect to a clinically meaningful extent.