Pharmacokinetic/Pharmacodynamic Index Linked to In Vivo Efficacy of the Ampicillin-Ceftriaxone Combination against Enterococcus faecalis.

Combination therapy with ampicillin plus ceftriaxone (AMP+CRO) is the first-line therapy for treating severe infections due to Enterococcus faecalis. However, the pharmacokinetic/pharmacodynamic (PK/PD) index linked to the in vivo efficacy of the combination is not yet defined, hindering dose optimization in the clinic. Because classical PK/PD indices are not directly applicable to antimicrobial combinations, two novel indices were tested in the optimized murine model of infection by E. faecalis to delineate the potentiation of AMP by CRO: the time above the CRO threshold (T>threshold) and the time above the AMP instantaneous MIC (T>MICi). The potential clinical relevance was evaluated by simulating human doses of AMP and CRO. Hill's equation fitted well the exposure-response data in terms of T>threshold, with a CRO threshold of 1 mg/L. The required exposures were 46%, 49%, and 52% for stasis and 1- and 2-log10 killing, respectively. Human ceftriaxone doses of 2 g every 12 h (q12h) would reach the target in >90% of strains with thresholds ≤64 mg/L. The AMP T>MICi index also fitted well, and the required exposures were 37%, 41%, and 46% for stasis and 1- and 2-log10 killing, respectively. In humans, the addition of CRO would allow use of lower AMP doses to reach the same T>MICi and to treat strains with higher MICs. This is the first report of the PK/PD indices and required magnitudes linked to AMP+CRO against E. faecalis; these results can be used as the basis to guide the design of clinical trials to improve combined therapy against enterococci.

Trastornos electrolíticos inducidos por fármacos y sustancias tóxicas / Electrolyte disorders induced by drugs and toxic substances

Las enfermedades pueden generar un desequilibrio de electrolitos como parte de su fisiopatología, al igual que los medicamentos usados crónicamente y algunas sustancias tóxicas disponibles en nuestro medio. A pesar de todos los datos estadísticos existentes, la incidencia global de los trastornos electrolíticos secundarios a fármacos o sustancias tóxicas permanece desconocida, y, posiblemente, subregistrada; por lo tanto, el objetivo de esta revisión es analizar los trastornos electrolíticos que causan algunos medicamentos y sustancias tóxicas, y describir el mecanismo a través del cual se producen las alteraciones, en particular, del sodio, potasio, magnesio, calcio y fósforo, con el fin de alertar a los profesionales de la salud en el momento de enfrentarse a este tipo de condiciones en su práctica clínica. El conocimiento de los efectos adversos relacionados con medicamentos y tóxicos es importante para prevenir, identificar y gestionar de forma eficaz, complicaciones que son potencialmente peligrosas. Esta revisión pretende ser un referente de apoyo para los profesionales de la salud en estas situaciones

Diseases can generate an electrolyte imbalance as part of their pathophysiology, as well as chronic use of some medications, and toxic substances available in our environment. Despite all the separate statistical data, the overall incidence of fluid and electrolyte disorders secondary to drugs or toxic substances remains unknown, and possibly underreported; therefore, the objective of this review is to analyze electrolyte disorders caused by some medications and toxic substances, and describe the mechanism through which changes in sodium, potassium, magnesium, calcium and phosphorus occur, in particular, in order to alert health professionals when facing this type of conditions in their clinical practice. Knowledge of drug and toxic-related adverse effects is important to effectively prevent, identify, and manage complications that can be potentially life-threatening. This review intends to be a reference for supporting health professionals in these situations