Clinically relevant drug-drug interactions of tacrolimus in the first week post-kidney transplantation recipients

This retrospective observational study aimed to investigate the prevalence and associated risk factors of clinically relevant drug-drug interactions of tacrolimus in kidney transplantation (KT) recipients during the first week post-transplantation. Medical records of tacrolimus-treated KT recipients were reviewed and DDIs were determined using two drug interaction programs. The presence of clinically relevant DDIs was confirmed by evaluating tacrolimus levels (C0) and adverse drug events through the drug interaction probability scale. This study enrolled 142 eligible KT recipients with mean potential DDIs in each patient of 7.8 and a standard deviation of 2.4. The majority type of potential DDIs was in the moderate category (84.0%). The prevalence of clinically relevant DDIs of tacrolimus was 18.6% (95% confidence interval: 11.4%–27.7%). Logistic regression analysis revealed that the number of potential DDIs significantly affected the likelihood of clinically relevant DDIs with tacrolimus, increasing the odds of experiencing clinically relevant immunosuppressant DDIs by 56%. These results provided compelling evidence for the substantial prevalence of clinically relevant DDIs of tacrolimus one-week post-KT and emphasized the importance of a comprehensive understanding of associated risk factors.