Association of Higher-Dose Fluoroquinolone Therapy With Serious Adverse Events in Older Adults With Advanced Chronic Kidney Disease.

Importance: Population-based data are needed to inform the safe prescribing of fluoroquinolone antibiotics to patients with advanced chronic kidney disease (CKD). Objective: To quantify the 14-day risk of a hospital visit with nervous system and/or psychiatric disorders, hypoglycemia, or a collagen-associated event in patients with advanced CKD newly prescribed a fluoroquinolone at a higher vs a lower dose. Design, Setting, and Participants: This population-based cohort study in Ontario, Canada (January 1, 2008, to March 17, 2020) used linked health care data to identify new users of fluoroquinolone antibiotics. Participants included adults 66 years or older with advanced CKD (an estimated glomerular filtration rate [eGFR] <30 mL/min/1.73 m2 but not receiving dialysis). Data analysis was performed from January 1 to April 30, 2021. Exposures: A new prescription for a higher-dose fluoroquinolone (ciprofloxacin, 501-1000 mg/d; levofloxacin, 501-750 mg/d; or norfloxacin, 401-800 mg/d) vs a lower-dose fluoroquinolone (ciprofloxacin, 500 mg/d; levofloxacin, 250-500 mg/d; or norfloxacin, 400 mg/d). Main Outcomes and Measure: The primary outcome was the 14-day risk of a hospital visit with nervous system and/or psychiatric disorders, hypoglycemia, or a collagen-associated event. Secondary outcomes included a hospital visit with sepsis, retinal detachment or other tendinopathies, all-cause hospitalization, all-cause mortality, and sudden cardiac death. Inverse probability of treatment weighting on the propensity score was used to balance comparison groups on baseline health. Weighted risk ratios and risk differences were obtained using modified Poisson regression and binomial regression, respectively. Results: Of 11 917 patients (median age, 83 years [IQR, 77-89 years]; 7438 women [62.4%]; median eGFR, 25 [IQR, 21-28] mL/min/1.73 m2) included in the analysis, 5482 (46.0%) received a higher-dose and 6435 (54.0%) received a lower-dose fluoroquinolone. After weighting, the primary composite outcome-a hospital visit with nervous system and/or psychiatric disorders, hypoglycemia, or a collagen-associated event-occurred in 68 of 5482 patients (1.2%) treated with a higher-dose fluoroquinolone and in 47 of 5516 (0.9%) treated with a lower-dose fluoroquinolone (weighted risk ratio, 1.45 [95% CI, 1.01-2.08]; weighted risk difference, 0.39% [95% CI, 0.01%-0.76%]). The risk of sepsis, retinal detachment, all-cause hospitalization, all-cause mortality, and sudden cardiac death did not differ significantly between groups. Conclusions and Relevance: These findings suggest that older patients with advanced CKD who were prescribed a fluoroquinolone at a higher-than-recommended dose were significantly more likely to experience the composite outcome of a hospital visit with nervous system and/or psychiatric disorders, hypoglycemia, or a collagen-associated event, although the absolute risk of these events was less than 2%.

Does Vitamin D Affect Chronic Renal Allograft Function in Pediatric Transplant Patients?

BACKGROUND Correction of hypovitaminosis D is simple, but it is unclear whether it is associated with an accelerated decline of renal allograft function in pediatric renal transplantation patients. This retrospective single center cohort study aimed at analyzing the effect of vitamin D and covariates on the slope of 1/creatinine after the first year. MATERIAL AND METHODS After ethics committee approval, 37 (14 male) pediatric renal transplant recipients on mycophenolate mofetil, who were followed between 2006 and 2014, were included in this study. We analyzed the slope of 1/creatinine, length of follow-up, average vitamin D levels, calcium, phosphate, alkaline phosphatase levels, intact parathyroid hormone (PTH) levels, and therapeutic drug monitoring parameters. RESULTS Median slope of 1/creatinine was -2.587e-006 L/µmol. We divided the 37 patients into two groups based on slope: 18 patients with a poorer slope and 19 patients with a good slope, with the median slope of 1/creatinine being significantly different between the two groups. Creatinine and cystatin C at one-year post-transplantation did not differ between the two groups. Average vitamin D levels were 71.4±31.01 pmol/L and identical in each group (averages 71.67 and 69.23 pmol/L, respectively). Only the mycophenolic acid coefficient of variation (MPA CV), which may promote formation of donor-specific antibodies, and PTH levels were significantly associated with 1/creatinine slope. CONCLUSIONS Our data suggest that the impact of mild and moderate decreased levels of vitamin D can have a mild impact on the progression of allograft dysfunction in transplant recipients. However, given the medication burden and adherence challenges in adolescents, correction of mildly decreased vitamin D levels may not be necessary.

A Retrospective Study on Mycophenolic Acid Drug Interactions: Effect of Prednisone, Sirolimus, and Tacrolimus With MPA.

Mycophenolic acid (MPA), the active compound of mycophenolate mofetil (MMF), is widely used as an antirejection drug after renal transplantation. There is growing evidence supporting the notion that there is substantial variability in the intra- and interpatient exposure to MPA. Drug interactions involving MPA with tacrolimus, steroids, and sirolimus have been understudied. The objective of this study was to determine the relationship between MPA, steroids, tacrolimus, and sirolimus. MPA trough concentrations from 37 pediatric renal transplant recipients (mean age 7.6 years at transplant) followed for a median follow-up of 7.8 years were analyzed retrospectively and 2131 dose-normalized MPA trough concentrations were evaluated against all known covariates including all concomitant immunosuppressant drug doses and exposure, age, albumin, hematocrit, and estimated glomerular filtration rate (eGFR). Age, hematocrit, and estimated glomerular filtration rate affected the dose-normalized MPA trough concentrations. The authors used appropriate linear regression univariate models and created 5 different multivariate models to examine individual drug-drug interactions (DDIs). Although the authors' findings support the notion that there is a DDI between MMF and both sirolimus and steroids, the sample size was small, and these findings should be confirmed in future studies. The authors found no DDIs between tacrolimus and MMF, the prodrug of MPA. These findings are important because there is a tendency to under-dose MMF early and to overdose late after transplantation. The DDI between sirolimus and MMF has not been described. Although therapeutic drug monitoring of MMF therapy is often not performed, the data presented here indicate a necessity for therapeutic drug monitoring. This is especially true when converting from tacrolimus to sirolimus, as a way to avoid MPA underexposure and organ rejection.

Developmental changes of MPA exposure in children.

BACKGROUND: Developmental changes (ontogeny) of drug disposition of Mycophenolate mofetil (MMF) have been understudied. METHODS: The charts of 37 pediatric renal transplant recipients (median age 7.3 years, median follow-up 7.8 (IQR 6.6, 14.3 years) who had regular mycophenolic acid (MPA) trough level monitoring in combination with tacrolimus (n = 31) or sirolimus (n = 6) therapy were analyzed retrospectively for their dose-normalized MPA exposure, steroid dose, albumin, hematocrit, and cystatin C estimated glomerular filtration rate (eGFR). Using appropriate univariate and multivariate methods, we determined whether MPA exposure was age dependent when controlling for the confounders. RESULTS: Dose-normalized MPA trough levels could be calculated in 2,128 (median 45/patient) instances. Spearman rank correlation analysis revealed that age correlated with dose-normalized MPA trough level for both body weight and body surface area, as well as serum albumin, hematocrit, steroid dose, and eGFR. In the multivariate analysis, serum albumin and steroid dose were not significant, and hematocrit only being significant when the youngest group of patients < 6 years of age was compared. eGFR was the most important confounder, but age dependency remained significant when controlling for all confounders. CONCLUSIONS: Small children are at a significantly greater risk for low MPA trough levels than adolescents, highlighting the need for pharmacokinetic monitoring of MPA.

Photo recall effect in association with cefazolin.

Patients in remission from local dermatitis secondary to external beam radiation treatments occasionally experience recurrence with systemic chemotherapy, a reaction termed radiation recall. Chemotherapy-induced photo recall from a prior exposure to the sun also has been reported. Rare reports describe photo recall effects from more commonly used medications. We report the case of a patient who developed a photo recall reaction after treatment with cefazolin. Results of the shave biopsy were consistent with a mild phototoxic eruption.