The Impact of Total Gastrectomy on Pharmacokinetics in Kidney Transplant Immunosuppressive Drug Regimes: A Case Study
Ensuring reliable gastrointestinal drug absorption of orally administered immunosuppressive medications posttransplant is critical to ensuring graft survival.Methods
A 66-year-old man of East Asian origin with a previous total gastrectomy was evaluated for living donor kidney transplantation. Pretransplant pharmacokinetic testing was performed to determine the most appropriate posttransplant medication strategy. The Gastrointestinal Quality of Life Index and Gastrointestinal Rating Scale questionnaires were administered to gauge immunosuppressive medication-related side effects in the absence of a stomach.Results
The patient's ability to absorb cyclosporin, tacrolimus (Tac), enteric-coated mycophenolate sodium (EC-MPS) and sirolimus (SRL) in oral dosage forms was well-preserved. Compared to nongastrectomy reference populations, the rate and extent of absorption of SRL and mycophenolic acid from EC-MPS were similar. The absorption of Tac and cyclosporin was greater than expected. Mycophenolate mofetil did not provide mycophenolic acid absorption as well as EC-MPS. The patient had worsened gastrointestinal symptoms with mycophenolate mofetil or EC-MPS in combination with Tac and cyclosporin, but this was not seen with isolated SRL.Conclusions
This case demonstrates that commonly used postkidney transplantation immunosuppressive regimes may be prescribed after total gastrectomy as long as their limitations are noted.