There is evidence showing the importance of reaching immunosuppressant target concentrations as soon as possible. The aim of this study was to evaluate the relationship between tacrolimus trough concentrations within the first week after transplantation and the rate of acute rejection. In this descriptive-analytic study, we included 57 renal transplant patients receiving tacrolimus as the primary immunosuppressive drug. After univariate analysis, donor age, duration of hospital stay, and creatinine clearance (third month) showed significant differences between rejecters and nonrejecters. In addition, mean tacrolimus trough concentrations on day 5, day 7, mean of days 1-7, and mean of days 5-7 were found to be significantly lower in rejecters (P = 0.009, P = 0.012, P = 0.006, and P = 0.035, respectively). Receiver operating characteristic curve analysis with tacrolimus trough concentrations measured on days 5 and 7 was able to discriminate between patients with and without acute rejection (P = 0.028 and P = 0.048 after Bonferroni correction). The tacrolimus trough concentration with the best sensitivity-specificity balance was 9.3 ng/mL on day 5 and 8.7 ng/mL on day 7. In the Kaplan-Meier analysis, patients with tacrolimus trough concentrations below 9.3 mg/mL on day 5 showed a lower survival time without acute rejection (P = 0.048 after correction) in comparison with patients with tacrolimus trough concentrations above this concentration. After logistic regression, we obtained a model relating rejection with sex, donor age, and tacrolimus trough concentrations on day 5 (P = 0.004). No significant relationship between tacrolimus trough concentrations and delta creatinine clearance from week 1 to month 3 was obtained. These results confirm that tacrolimus trough concentrations during the first week are an important predictor of acute rejection. Therefore, it is critical to reach target blood concentrations of tacrolimus as soon as possible to improve allograft survival.

Objective. Knowledge and quantification of the microcirculation are very important for estimating the status of an organ. Real-time contrast-enhanced sonography assesses microvascular tissue perfusion. This technique has been proposed as innocuous; however, data from experimental animals (rats) have shown renal interstitial microhemorrhage after the procedure. Therefore, we developed a porcine model to explore potential renal damage that in situ exposure might cause. Methods. Kidneys from 8 anesthetized pigs were surgically exposed. An ultrasound contrast agent (sulfur hexafluoride) was infused through the femoral vein in a continuous perfusion. Destructive ultrasonic flashes were applied with a high mechanical index over only 1 kidney (the contralateral kidney was used as a control). Blinded histologic and laboratory analyses were performed to reveal any lesions. Results. Histologic analysis of the kidney samples showed no evidence of renal damage. Biochemical parameters that could represent renal tissue damage and hemoglobin levels did not change after the microbubble-ultrasound interaction. Conclusions. The ultrasound contrast agent-ultrasound interaction in anesthetized pig kidneys under the output level for the imaging visualization and microbubble destruction used did not cause tissue damage. Our results suggest that this procedure could be used in humans for regular analysis of the kidney microcirculation with minimal risk of tissue damage.

Data collected were demographic, the drug class involved (anatomical chemical therapeutic (ATC)), DRP detected and degree of recommendation acceptance. Results Total patients with DRP: 291 (23.3%). Identified DRP: 393 (1.4 DRP/patient). 58.3% were men and median age was 63 (15.7) years. Conclusion and relevance Almost 25% of all patients had a DRP, presenting an incidence of 1.4 DRP/patient, higher than reported in previous series. 83% of evaluable recommendations were accepted. One-third of the recommendations were derived from a wrong dosage, and 15% from drug interactions. Hydroxychloroquine was the most frequently involved drug, probably because of the limited experience and wide spectrum of interactions, followed by antimicrobials such as ceftriaxone and azithromycin, used widely in respiratory tract infections.

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