Results of a Phase 1 Multicentre Investigation of Dexmedetomidine Bolus and Infusion in Corrective Infant Cardiac Surgery

BACKGROUND: Dexmedetomidine (DEX) is increasingly used intraoperatively in infants undergoing cardiac surgery. This phase 1 multicentre study sought to: (i) determine the safety of DEX for cardiac surgery with cardiopulmonary bypass; (ii) determine the pharmacokinetics (PK) of DEX; (iii) create a PK model and dosing for steady-state DEX plasma levels; and (iv) validate the PK model and dosing. METHODS: We included 122 neonates and infants (0-180 days) with D-transposition of the great arteries, ventricular septal defect, or tetralogy of Fallot. Dose escalation was used to generate NONMEM® PK modelling, and then validation was performed to achieve low (200-300 pg ml RESULTS: Five of 122 subjects had adverse safety outcomes (4.1%; 95% confidence interval [CI], 1.8-9.2%). Two had junctional rhythm, two had second-/third-degree atrioventricular block, and one had hypotension. Clearance (CL) immediately postoperative and CL on CPB were reduced by approximately 50% and 95%, respectively, compared with pre-CPB CL. DEX clearance after CPB was 1240 ml min CONCLUSIONS: When used with a careful dosing strategy, DEX results in low incidence and severity of adverse safety events in infants undergoing cardiac surgery with cardiopulmonary bypass. This validated PK model should assist clinicians in selecting appropriate dosing. The results of this phase 1 trial provide preliminary data for a phase 3 trial of DEX neuroprotection

Identification of Post-cardiac Arrest Blood Pressure Thresholds Associated With Outcomes in Children: An ICU-Resuscitation Study

INTRODUCTION: Though early hypotension after pediatric in-hospital cardiac arrest (IHCA) is associated with inferior outcomes, ideal post-arrest blood pressure (BP) targets have not been established. We aimed to leverage prospectively collected BP data to explore the association of post-arrest BP thresholds with outcomes. We hypothesized that post-arrest systolic and diastolic BP thresholds would be higher than the currently recommended post-cardiopulmonary resuscitation BP targets and would be associated with higher rates of survival to hospital discharge. METHODS: We performed a secondary analysis of prospectively collected BP data from the first 24 h following return of circulation from index IHCA events enrolled in the ICU-RESUScitation trial (NCT02837497). The lowest documented systolic BP (SBP) and diastolic BP (DBP) were percentile-adjusted for age, height and sex. Receiver operator characteristic curves and cubic spline analyses controlling for illness category and presence of pre-arrest hypotension were generated exploring the association of lowest post-arrest SBP and DBP with survival to hospital discharge and survival to hospital discharge with favorable neurologic outcome (Pediatric Cerebral Performance Category of 1-3 or no change from baseline). Optimal cutoffs for post-arrest BP thresholds were based on analysis of receiver operator characteristic curves and spline curves. Logistic regression models accounting for illness category and pre-arrest hypotension examined the associations of these thresholds with outcomes. RESULTS: Among 693 index events with 0-6 h post-arrest BP data, identified thresholds were: SBP \u3e 10th percentile and DBP \u3e 50th percentile for age, sex and height. Fifty-one percent (n = 352) of subjects had lowest SBP above threshold and 50% (n = 346) had lowest DBP above threshold. SBP and DBP above thresholds were each associated with survival to hospital discharge (SBP: aRR 1.21 [95% CI 1.10, 1.33]; DBP: aRR 1.23 [1.12, 1.34]) and survival to hospital discharge with favorable neurologic outcome (SBP: aRR 1.22 [1.10, 1.35]; DBP: aRR 1.27 [1.15, 1.40]) (all p \u3c 0.001). CONCLUSIONS: Following pediatric IHCA, subjects had higher rates of survival to hospital discharge and survival to hospital discharge with favorable neurologic outcome when BP targets above a threshold of SBP \u3e 10th percentile for age and DBP \u3e 50th percentile for age during the first 6 h post-arrest

A simple and selective liquid chromatography- tandem mass spectrometry method for determination of ε-aminocaproic acid in human plasma

Understanding the clinical pharmacology of the antifibrinolytic drug epsilon-aminocaproic acid (EACA) is critical for rational drug administration in children. The aim of this study is to develop a reliable assay for the determination of EACA in human plasma. We describe a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) assay for EACA in human plasma. Sample preparation involved plasma dilution (1:2040), followed by reversed-phase chromatographic separation and selective detection using tandem mass spectrometry. EACA had a linear range of 1 - 250 μg/mL. The intraday precision based on the standard deviation of replicates of quality control samples ranged from 4.7 to 10.4% and the accuracy ranged from 92-106%. The interday precision ranged from 4.6 to 9.8% and the accuracy ranged from 95-103%. Stability studies showed that EACA was stable during the conditions for sample preparation and storage. The described method is robust and successfully employed for clinical studies of EACA in childre

Liquid Chromatography-Tandem Mass Spectrometry Assays for Therapeutic Drug Monitoring of Cefepime

With the development and growth of multi-drug resistance organisms, therapeutic drug monitoring (TDM) has become an increasingly common tool to assure the efficacy and safety of antimicrobial therapy. The requirement for TDM has not routinely extended to cephalosporins, such as cefepime, due to their wide therapeutic window. However, the implementation of TDM for cefepime is becoming increasingly important as many Gram-negative bacteria have adapted mechanisms that increase resistance to antimicrobials and therefore require higher concentrations of cefepime for bacterial eradication. Additionally, pharmacokinetic variability and difficulty in treating patients, especially those who are critically ill or those with renal dysfunction, necessitate TDM to ensure optimal cefepime concentrations. This review aims to assess and evaluate the techniques currently utilized to quantify cefepime in both plasma and serum in terms of usefulness for feasible and readily adaptable bedside cefepime TDM

Rational dosing of HCQ for COVID-19_pre-print

Background: Hydroxychloroquine (HCQ) has in vitro activity against SARS-CoV-2. However, data to inform optimal human dosing are limited. Methods: We conducted Monte Carlo simulations of HCQ sulfate using a published population pharmacokinetic model. The model informing our simulations described a 2-compartment linear model with first-order absorption with a lag, derived from plasma HCQ concentration data from 22 healthy adults and 69 patients with malaria. Using the final PK model, we performed 1000 simulations for the plasma concentrations of HCQ sulfate based on various approved dosages (i.e. acute malaria, autoimmune conditions) and proposed dosing regimens for treatment of COVID-19. The results of simulations were used to derive the area under the concentration-time curve (AUC), maximal concentration, and time to maximal concentration for each evaluated regimen. Results: The use of a loading dose, as with acute malaria dosing, resulted in rapid achievement of maximal concentrations early in the treatment course, which were maintained with daily dosing thereafter. The use of once or twice daily doses without a loading dose led to slowly increasing plasma concentrations through day 10. Simulated regimens that employed an 800 mg loading dose for adults (13 mg/kg for children) followed by 400 mg at 6 or 12 hours (6.5 mg/kg for children) achieved the greatest AUC0-24. Conclusions: Based on our findings, along with established safety data from malarial studies, we believe that approved dosing for treatment acute malaria is the most reasonable and safest approach if HCQ will be used to treat COVID-19

Prescribing habits and caregiver satisfaction with resources for dosing children: Rationale for more informative dosing guidance

Abstract Background Physicians, nurses and hospital pharmacists were surveyed to assess attitudes of hospital-based pediatric caregivers regarding the dosing of medicine to children. Our objectives were to gauge how current resources are utilized to guide the management of pediatric pharmacotherapy, assess drugs and drug classes where guidance is most critical and examine the prevalence and practice of dose adjustment in pediatric patients. Methods Questionnaire categories included demographics, pharmacotherapy resources, dosing adjustment and modification, and valuation of additional tools to provide improved pharmacotherapy guidance. The questionnaire was developed in collaboration with representative nurse, pharmacist and physician team members using the SurveyMonkey.com site and survey tool. The survey link was distributed to caregivers via email. The questionnaire results of 303 respondents were collected into MS Excel and imported into SAS for data summarization. Results A total of 313 responses were obtained. Physician and nurse practitioner groups comprised the majority of the responses. Approximately 80% of the responders considered dosing adjustment important in pediatric pharmacotherapy. While there was general satisfaction with available resources, nearly 75% responded in support of access to predictive tools that facilitate individualized patient pharmacotherapy. The majority of respondents (> 65%) indicated that dosing outside standard practice occurs in 1-20% of their patients, while still a substantial number of respondents (a range of 8 to 20% reflecting the resident and fellow categories) estimated between 20 and 50% of their patients required adjustments outside the standard practice. Conclusions Differences in prescribing habits based on caregiver role, specialty and location were small and likely require further exploration. Existing resources are generally viewed as helpful but inadequate to guide recommendations for individual patients. Decision support systems connected to hospital-based electronic medical records offer the promise of informative and individualized pharmacotherapy guidance.</p

A pharmacokinetic analysis of tobramycin in patients less than five years of age with cystic fibrosis: Assessment of target attainment with extended-interval dosing through simulation

Extended interval dosing of tobramycin is recommended for treatment of pulmonary exacerbations in adults and older children with cystic fibrosis (CF), but data are limited in patients less than 5 years of age. We performed a retrospective population pharmacokinetic (PK) analysis of hospitalized children with CF \u3c5 years of age prescribed intravenous tobramycin for a pulmonary exacerbation from March 2011 to September 2018 at our hospital. Children with normal renal function who had ≥1 tobramycin concentration available were included. Nonlinear mixed effects population PK modeling was performed using NONMEM using data from the first 48 h of tobramycin treatment. Monte Carlo simulations were implemented to determine the fraction of simulated patients that met published therapeutic targets with regimens of 10-15 mg/kg/day once-daily dosing. Fifty-eight patients received 111 tobramycin courses (range 1-9/patient). A two-compartment model best described the data. Age, glomerular filtration rate, and vancomycin coadministration were significant covariates on tobramycin clearance. The typical values of clearance and central volume of distribution were 0.252 L/hr/kg^0.75 and 0.308 L/kg, respectively. No once-daily regimens achieved all pre-specified targets simultaneously in \u3e75% of simulated subjects. A dosage of 13 mg/kg/dose best met the predefined targets of

A pharmacokinetic analysis of tobramycin in patients less than five years of age with cystic fibrosis: Assessment of target attainment with extended-interval dosing through simulation

Extended interval dosing of tobramycin is recommended for treatment of pulmonary exacerbations in adults and older children with cystic fibrosis (CF), but data are limited in patients less than 5 years of age. We performed a retrospective population pharmacokinetic (PK) analysis of hospitalized children with CF \u3c5 years of age prescribed intravenous tobramycin for a pulmonary exacerbation from March 2011 to September 2018 at our hospital. Children with normal renal function who had ≥1 tobramycin concentration available were included. Nonlinear mixed effects population PK modeling was performed using NONMEM using data from the first 48 h of tobramycin treatment. Monte Carlo simulations were implemented to determine the fraction of simulated patients that met published therapeutic targets with regimens of 10-15 mg/kg/day once-daily dosing. Fifty-eight patients received 111 tobramycin courses (range 1-9/patient). A two-compartment model best described the data. Age, glomerular filtration rate, and vancomycin coadministration were significant covariates on tobramycin clearance. The typical values of clearance and central volume of distribution were 0.252 L/hr/kg^0.75 and 0.308 L/kg, respectively. No once-daily regimens achieved all pre-specified targets simultaneously in \u3e75% of simulated subjects. A dosage of 13 mg/kg/dose best met the predefined targets of