Tailored Rabbit Antithymocyte Globulin Induction Dosing for Kidney Transplantation.

BACKGROUND: Rabbit antithymocyte globulin (rATG) is the most widely used kidney transplant induction immunotherapy in the United States. It was recently Food and Drug Administration approved for this indication with typical dose recommendations of 1.5 mg/kg for up to 7 days given via a central line. METHODS: We theorized that reduced rATG dosing when compared with conventional dosing (6-10.5 mg/kg) is safe and effective, leading to development of a risk-stratified treatment protocol. Five-year data from a retrospective cohort of 224 adult kidney transplants (2008-2013) with follow-up through 2015 is presented. Cumulative rATG doses of 3 mg/kg were administered peripherally to nonsensitized living donor recipients, 4.5 mg/kg to nonsensitized deceased donor recipients. A subset of higher immunologic risk recipients (defined as history of prior transplant, panel reactive antibody greater than 20%, or flow cytometry crossmatch positivity) received 6 mg/kg. RESULTS: There were no differences in patient or graft survival between the 3 groups. One-year rejection rates in the first 2 groups were 8.3% and 8.8%, respectively, comparable to contemporaneous rates reported to the Scientific Registry of Transplant Recipients. Dose tailoring permitted substantial cost savings estimated at US $1 091 502. Mean length of stay fell by almost 3 days as the protocol was refined. There were no episodes of phlebitis. Infection rates were comparable with those reported to the Scientific Registry of Transplant Recipients. CONCLUSIONS: The novel findings of the current study include peripheral administration, reduced dosing, favorable safety, excellent allograft outcomes, and clear associative data regarding reduced costs and length of stay.

Tacrolimus interaction with nafcillin resulting in significant decreases in tacrolimus concentrations: A case report.

Tacrolimus (TAC) is subject to many drug interactions as a result of its metabolism primarily via CYP450 isoenzyme 3A4. Numerous case reports of TAC and CYP3A4 inducers and inhibitors have been described including antimicrobials, calcium channel antagonists, and antiepileptic drugs. We present the case of a 13-year-old patient with cystic fibrosis and a history of liver transplantation, where subtherapeutic TAC concentrations were suspected to be a result of concomitant TAC and nafcillin (NAF) therapy. The observed drug interaction occurred on two separate hospital admissions, during both of which the patient exhibited therapeutic TAC concentrations prior to exposure to NAF, a CYP3A4 inducer. Upon discontinuation of NAF, TAC concentrations recovered in both instances. This case represents a drug-drug interaction between TAC and NAF that has not previously been reported to our knowledge. Despite the lack of existing reports of interaction between these two agents, this case highlights the importance of therapeutic drug monitoring and assessing for any potential drug-drug or drug-food interactions in patients receiving TAC therapy.

Successful eculizumab treatment of recurrent postpartum atypical hemolytic uremic syndrome after kidney transplantation.

Postpartum atypical hemolytic uremic syndrome (aHUS) is a rare disorder associated with poor maternal and fetal outcomes. We describe a case of severe postpartum aHUS with recurrence in a kidney allograft after a second pregnancy. The patient had initially presented age 28 years with aHUS that developed after her first delivery. In spite of treatment with plasma exchange, she developed end-stage renal disease (ESRD) requiring years of hemodialysis before receiving a kidney transplant from a living unrelated donor. Two years later, she became pregnant again and at 26 weeks gestation she presented to our hospital with hypertension and proteinuria. Within 48 hours of delivery she developed hemolytic anemia, thrombocytopenia, and oliguric acute kidney injury (AKI) culminating in the need for dialysis. There was no response to therapeutic plasma exchange (TPE). However, treatment with eculizumab led to prompt, successful resolution of hemolysis, thrombocytopenia, and AKI. Three months after therapy was stopped, her disease relapsed causing renal failure again requiring dialysis. At that time, an allograft biopsy revealed severe thrombotic microangiopathy (TMA). Eculizumab was resumed without plasma exchange leading to resolution of aHUS and return of kidney function. Now, her baby is nearly 2 years old. She remains on maintenance eculizumab therapy 1,200 mg every 2 weeks without dialysis. She has excellent renal function with creatinine of 1.2 mg/dL, eGFR 52 mL/min/1.73 m, and proteinuria 0.35 g/day. She will likely be on eculizumab for the remainder of her life.

Use of computer alerts to prevent the inappropriate use of metformin in an inpatient setting.

BACKGROUND: Metformin is recommended as initial therapy for most patients with type 2 diabetes mellitus. Its most serious adverse effect, lactic acidosis, is a rare entity with a high mortality rate. Despite well-publicized contraindications, metformin is inappropriately prescribed to many hospitalized patients. OBJECTIVE: To determine the efficacy of computer alerts at reducing inappropriate metformin prescribing. METHODS: Retrospective chart review of all hospitalized patients who received an order for metformin, before (n = 144) and after (n = 147) an intervention designed to reduce inappropriate administration. This intervention included 2 "hard-stop" computer alerts that prevented prescribing metformin to patients with renal dysfunction and in critical care or postoperative units; and 2 "soft" alerts that fired when no serum creatinine was available or the patient was in an outpatient surgical unit. Charts were reviewed for the presence of contraindications: renal insufficiency, congestive heart failure, recent myocardial infarction, surgery, or intravenous contrast use within 48 hours of metformin administration. RESULTS: In the preintervention group there were 47 violations compared with 13 violations in the postintervention group (P < .001). The greatest improvement was in surgical patients (39 violations vs 11, P < .001). CONCLUSIONS: Computer alerts at order entry were effective in decreasing the inappropriate prescribing of metformin in an inpatient setting.

Correlation of bivalirudin dose with creatinine clearance during treatment of heparin-induced thrombocytopenia.

STUDY OBJECTIVES: To evaluate steady-state bivalirudin dosing requirements in patients with a wide range of kidney function who were being treated for heparin-induced thrombocytopenia (HIT)-related disorders. DESIGN: Retrospective medical record review. SETTING: Academic medical center. PATIENTS: Sixty-four adults with varying degrees of renal function who were receiving bivalirudin for at least 48 hours for HIT-related disorders between March 2007 and May 2010. MEASUREMENTS AND MAIN RESULTS: Steady-state conditions were defined as a constant bivalirudin infusion dose for at least 12 hours, with serum creatinine concentration varying less than 20% for 48 hours (for patients not receiving renal replacement therapy) and at least two therapeutic activated partial thromboplastin time (aPTT) values (60-80 sec). Patients were assigned to five groups based on Cockcroft-Gault-estimated creatinine clearance (Clcr) of less than 30, 30-60, or greater than 60 ml/minute, or by type of renal replacement therapy-intermittent hemodialysis or continuous venovenous hemofiltration (CVVH). For Clcr greater than 60 ml/minute, the median bivalirudin dose was 0.15 mg/kg/hour (interquartile range [IQR] 0.11-0.15 mg/kg/hr), which was greater than median doses for Clcr 30-60 ml/minute (0.10 mg/kg/hr, IQR 0.06-0.13 mg/kg/hr, p=0.004), Clcr less than 30 ml/minute (0.08 mg/kg/hr, IQR 0.04-0.1 mg/kg/hr, p=0.001), CVVH (0.06 mg/kg/hr, IQR 0.03-0.10 mg/kg/hr, p=0.046), and hemodialysis (0.04 mg/kg/hr, IQR 0.03-0.05 mg/kg/hr, p=0.0001). Bivalirudin doses correlated with Clcr (Spearman r = 0.58, p<0.01). The median aPTT value of 70 seconds (IQR 63-74 sec) was similar in all groups. Thrombosis was present before bivalirudin therapy in 18 (28%) of 64 patients, and two patients (3%) developed thromboemboli during bivalirudin therapy. Clinically significant bleeding related to bivalirudin and leading to discontinuation of bivalirudin occurred in four patients (6%). The median international normalized ratio increased from 1.5 (IQR 1.3-1.7) before bivalirudin therapy to 1.9 (IQR 1.8-2.1) during bivalirudin therapy (p=0.002) in 11 patients who were not receiving warfarin. CONCLUSION: Bivalirudin dosing requirements increased with increasing Clcr values. The high degree of variability suggests that dosing in individual patients will require careful titration to achieve adequate anticoagulation.