COVID-19治療中に腎移植患者のタクロリムス血中濃度が上昇した2症例

抄録

Tacrolimus is used for various organ transplants, suppressing autoimmune diseases like rheumatoid arthritis and myasthenia gravis. Tacrolimus is metabolized by cytochrome P450 and a substrate of P-glycoprotein, and many drugs affect the pharmacokinetics of tacrolimus. In Kagoshima University Hospital, tacrolimus is administered to patients after renal transplantation, and continuous therapeutic drug monitoring (TDM) is performed. There're two cases that tacrolimus blood levels significantly increased after receiving therapy against SARS-CoV-2; these patients were taking tacrolimus to suppress rejection after renal transplantation. The first case was a kidney transplant performed six years ago. The patient was hospitalized for COVID-19. On the first day, remdesivir was started. The dose of tacrolimus was reduced from the third day due to decreased renal function. Afterward, the blood concentration of tacrolimus remained high until the sixth day of hospitalization despite decreasing the administration dose. After discharge, the blood concentration of tacrolimus on the 17th day showed a decrease and returned to the pre-hospital concentration on the 49th day. The second case was a kidney transplant performed 11 months ago. The patient was hospitalized for COVID-19 and started remdesivir on the third day. The tacrolimus blood concentration increased on the fourth day. During hospitalization, the concentration of tacrolimus remained high while the administration dose was decreased. After discharge, the concentration gradually decreased while still being controlled. These cases suggest that blood concentration of tacrolimus, and hepatic and renal function, should be monitored and the dose should be carefully adjusted when administered in combination with remdesivir.