Gastrointestinal side effects of mycophenolic acid in renal transplant patients: a reappraisal.

Patient and graft survival following renal transplantation have improved markedly over the past decade, meaning that physician attention has turned more towards minimizing short- and long-term toxicities associated with immunosuppressive regimens. Gastrointestinal (GI) adverse events are common following renal transplantation and all immunosuppressive regimens have been associated with such events. Mycophenolate mofetil (MMF) or enteric-coated mycophenolate sodium (EC-MPS) are potential components of immunosuppression regimens, and are associated with the most successful outcomes in kidney transplantation. The effects of MMF and EC-MPS are likely mediated via the active metabolite mycophenolic acid (MPA). The GI events caused by both MMF and EC-MPS may, in part, be related to MPA, independent of the formulation or route of administration. MPA may produce GI events either through direct action or through the action of it metabolites. However, many other factors may cause GI events observed following renal transplantation. These include the surgery itself and concurrent diseases such as diabetes, and bacterial, viral, fungal and parasitical infections. Additionally, numerous concomitant non-immunosuppressive agents, including antibiotics hypoglycaemic and proton-pump inhibitors, can be associated with GI events. In a recent trial in renal transplant patients with severe diarrhoea, approximately 50% of patients achieved resolution of diarrhoea through methods other than altering their immunosuppressive regimens. Indeed altering of the immunosuppressive regimen may lead to the risk of acute rejection. Thus, in order to reduce the risk of rejection and subsequent damage to the graft, it is important to consider other causes of GI events in renal transplant patients before altering immunosuppressive regimens.