Resumen de Low daily dose of tacrolimus in a kidney transplant patient treated with hiv-1 therapy containing darunavir-ritonavir
Ariadna Padullés Zamora, Montserrat Cols, Edoardo Melilli, Francisco Rigo Raul, María Saumoy, Elisabeth Leiva, Oriol Bestard Matamoros, Josep Maria Cruzado Garrit, Núria Padullés Zamora
Introduction: Severe drug-drug interactions with tacrolimus and HIV-1 protease inhibitors have been reported. Both drugs are cornerstones of modern immunosuppressive and HIV-1 therapy, and both are substrates of the cytochrome P-450 3A4 system of the liver and the intestinal P-gp. We report a kidney transplant patient who experienced elevation of tacrolimus concentrations due to CYP 3A4 inhibition secondary to the initiation of darunavir/ritonavir and was successfully switched to a very low daily dose of tacrolimus.
Case report: A 55 year-old HIV+ man with chronic kidney disease underwent an orthotopic kidney transplant (KT). Tacrolimus was started on day 4 after-KT and c-ART on day 5. Consequently, TAC levels rose to 28.7 ug/L requiring drug discontinuation.Blood concentration on day 12 declined to 9.8 ug/L. Tacrolimus was restarted (0.05 mg daily) using a 0.01 mg/mL suspension, that was stable for 30 days at 2-8ºC. The patient was stabilized on a tacrolimus dose of 0.04 mg/24 h and Area Under the Curve (AUC) value was within the therapeutic range.
Conclusion:Balancing tacrolimus with c-ART that includes PI requires a careful monitoring. A tacrolimus suspension was successfully administered, as the pharmacokinetic analysis resulted in stable tacrolimus levels over time and AUC 0-24 results within the desired range. Possible blood levels fluctuations were avoided, as well as the toxicity while maintaining adequate concentrations to prevent organ rejection
