Isavuconazole-tacrolimus drug-drug interactions in HSCT patients.

OBJECTIVES: Because tacrolimus has a narrow therapeutic window and exhibits both intraindividual and interindividual variability, we attempted to establish the percentage of calcineurin inhibitor (CNI) dose reduction to prevent toxicity and ensure stem cell engraftment when using this immunosuppressant with the antifungal isavuconazole (ISA). By calculating the tacrolimus concentration/dose (C/D) ratio, we expected to demonstrate the magnitude of change in the C/D ratio from baseline after ISA administration. METHODS: We evaluated the interaction between ISA, a new triazole antifungal used in prophylaxis for invasive fungal infections, and the CNI class of immunosuppressive drugs, specifically tacrolimus, in 11 blood samples from HSCT recipients. RESULTS: The mean tacrolimus C/D ratio increased 1.44-fold from baseline 48 h after ISA administration (P = 0.001). CONCLUSIONS: Although further investigation is needed, the results of this study suggest that a reduction of 18% in tacrolimus may be recommended.

[Set up of a protocol for heparin use in special patients]. / Establecimiento de un protocolo para el uso de la heparina en pacientes con características especiales.

Low-molecular weight (LMW) heparins bring a series of advantages as compared to non-fractionated heparin (NFH), such as safety, efficacy, bioavailability, fewer monitoring, and persistent anti-coagulant response. There exist, however, a concern about their use in particular patients that may require a special control, such as those with renal failure, age over 75 years, obesity, and pregnancy. The aim of this study was the set up between the department of Pharmacy, Hematology, and Internal Medicine of a consensus protocol for the follow-up ad monitoring of LMWH in patients requiring a special control. For this purpose, we carried out a bibliographical review of the different heparins used under de above mentioned conditions. Based on the evidence available and the consensus among the members of the working group, we established a protocol that contained recommendations on prophylaxis, management and monitoring by means of the determination of anti-Xa factor. Besides, we included some clues on the therapeutic figures of anti-Xa and administration schedules for obtaining anti-Xa values within the range. Enoxaparin was the selected heparin given the evidence and its availability at our center.

Las HBPMs (heparina de bajo peso molecular) tienen numerosas ventajas sobre la heparina no fraccionada (HNF) como seguridad, eficacia, biodisponibilidad, menor monitorización y una respuesta anticoagulante persistente. Pero, existe cierta preocupación en su manejo para determinados pacientes que requieren un control especial como en insuficiencia renal, mayores de 75 años, obesidad y embarazo. El objetivo de este estudio fue la realización de un protocolo consensuado entre los Servicios de Farmacia, Hematología y Medicina Interna, para el seguimiento y monitorización de HBPM en pacientes que requieren un especial control. Para ello, llevamos a cabo una revisión bibliográfica de las distintas heparinas en las situaciones comentadas. Basándonos en la evidencia disponible y en el consenso entre los miembros del grupo de trabajo, elaboramos el protocolo, recomendando unas dosis para profilaxis, tratamiento y monitorización, mediante la determinación del factor anti-Xa. Además, recogemos unas orientaciones sobre los valores terapéuticos del anti-Xa y unas pautas posológicas para la obtención de un anti-Xa en rango. La heparina seleccionada fue la enoxaparina, por su evidencia y disponibilidad en nuestro centro.