Elexacaftor/Tezacaftor/Ivacaftor use in Pediatric Cystic Fibrosis Patients with Advanced Liver Disease.

BACKGROUND: Cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy extends the life expectancy of people with cystic fibrosis (PwCF). However, CFTR modulators have not been well studied in patients with cystic fibrosis liver disease (CFLD), specifically those with advanced liver disease with portal hypertension. The purpose of this report is to describe the use of elexacaftor/tezacaftor/ivacaftor (ETI) in pediatric CF patients with advanced CFLD. METHODS: This retrospective case series included PwCF < 18 years old with baseline advanced CFLD initiated on ETI. RESULTS: Eleven PwCF and advanced CFLD were treated with ETI; six started a reduced dose regimen. No patient required treatment interruption and four patients received dose changes related to increase in transaminase and/or bilirubin elevations. Mean (SD) change in ppFEV1 from prior to ETI to highest value during therapy was 14.27 % (4.25) (p = 0.007). When evaluating the group as whole, AST decreased from baseline to last reported -15.18 (23.23) units/L (p = 0.054) and ALT slightly increased 0.73 (39.13) units/L (p = 0.96). Bilirubin increased minimally overall for patients with mean change from baseline of 0.83 (1.33) mg/dL [range -0.5-3] (p = 0.17). A model for time on ETI showed a significant decrease in AST over time of 0.955 per month of ETI but no other liver biochemistries were significant. No patient experienced decompensation of CFLD. CONCLUSION: ETI therapy in pediatric CF patients with advanced CFLD can be beneficial in improving pulmonary and nutritional outcomes without negative impact on liver biochemistries or hepatic outcomes. Close monitoring is recommended to ensure safety and tolerability.

Educational Initiative to Increase Knowledge for Transition to Adult Care in Adolescents With Cystic Fibrosis.

OBJECTIVE: Preparation for transition from pediatric to adult cystic fibrosis (CF) care is essential for successful self-management in adulthood. The primary objective of this study was to determine if education improved performance on follow-up assessments to increase knowledge for transition into adult care. The secondary objective of this study was to identify areas of greatest educational opportunity for adolescent CF patients. METHODS: A knowledge assessment containing 13 multiple-choice questions was given to patients between 14 and 19 years of age. Three educational handouts covering topics including nutrition, pancreatic enzyme replacement therapy, or vitamins were provided when a question corresponding to the topic was answered incorrectly. The same assessment was completed at the next clinic appointment as a follow-up. The scores of initial and follow-up assessments were compared based on number of correct answers. Additionally, the number of educational handouts provided was analyzed to determine area of greatest educational need. RESULTS: The average score ± SD on the initial assessment was 8.3 ± 1.6 of 13 questions answered correctly. For patients who completed both assessments, scores improved significantly between initial and follow-up assessments (8.4 ± 1.8 before education vs 10.3 ± 1.1 after; p = 0.0008). Nutrition, pancreatic enzyme, and vitamin handouts were given to 14 (70%), 17 (85%), and 20 (100%) patients, respectively. CONCLUSIONS: This pharmacist-driven educational initiative increased knowledge assessment scores after education was provided. Future studies of similar knowledge assessments starting at younger ages and other disease topics may determine if targeted education is the optimal way to build knowledge for transition to adult CF care.

Evaluation of the safety of piperacillin-tazobactam extended infusion in pediatric cystic fibrosis patients.

BACKGROUND: Patients with cystic fibrosis (CF) may be treated with piperacillin-tazobactam (PZT) for acute pulmonary exacerbations. Extending the infusion of PZT is one strategy to increase efficacy. Direct comparison, with respect to the incidence of acute kidney injury (AKI), between these two strategies has not been evaluated in pediatric patients with CF. The primary objective of this study was to compare the incidence of AKI in pediatric CF patients receiving extended infusion (EI) PZT versus traditional infusion (TI). METHODS: This IRB-approved, retrospective analysis included patients ages 30 days to 18 years that received PZT for at least 48 h between January 1, 2008, and January 1, 2020. PZT was infused over 30 min (TI group) or 4 h (EI group). RESULTS: Two hundred and four patients were included (TI: 109, EI: 95). Median age was 8 years (4-13) and 7 years (3-12) in the TI and EI groups (p = 0.15). The groups did not differ significantly in their baseline characteristics. There were 12 (11%) AKIs in the TI group and 8 (8.4%) in the EI group (p = 0.53). There was one occurrence of serum sickness in the TI group and none in the EI group. The incidence of thrombocytopenia was similar between the two groups. Median treatment duration was 8 days (5-11) and 9 days (5-13) for the TI and EI groups, respectively (p = 0.24). CONCLUSIONS: There was no significant increase in AKI in pediatric patients with CF receiving PZT by EI compared with TI. EI may be utilized to optimize the pharmacokinetics of PZT in pediatric CF patients.

Evaluation of the safety of cefepime prolonged infusions in pediatric patients with cystic fibrosis.

OBJECTIVE: Pediatric cystic fibrosis (CF) patients possess unique pharmacokinetics and may benefit from prolonged beta-lactam infusions to optimize pharmacodynamics. This study compared adverse drug event (ADE) rates with cefepime prolonged (PI) and standard infusions (SI). METHODS: This retrospective study included pediatric patients treated with cefepime for CF exacerbations between 2009 and 2019. One encounter per patient was analyzed with prioritization of SI encounters given sample size limitations. Baseline lab abnormalities, seizure disorders, and bleeding were exclusion criteria. The primary outcome was a composite safety endpoint (acute kidney injury [AKI], hepatotoxicity, hematologic toxicity, neurotoxicity, and hypersensitivity). RESULTS: Of 188 patients, 135 received PI and 53 received SI. Baseline characteristics were similar between groups. More PI patients used CF transmembrane conductance regulator (CFTR) modulators (25% vs. 0%, p < 0.01) or had antibiotic allergies (62% vs. 38%, p = 0.02). Difference in rates of composite safety endpoint was not statistically significant between PI and SI (21 [15.6%] vs. 6 [11.3%] p = 0.46) nor was incidence of AKI (16 [11.8%] vs. 6 [11.3%], p = 0.92). Other ADEs were rarely observed. Length of stay (12.2 vs. 10.1 days, p = 0.06), change in discharge ppFEV1 from admission (13 vs. 12, p = 0.91) or from baseline (-4 vs. -6.5, p = 0.33), and time to next exacerbation (249.7 vs. 192.5 days, p = 0.93) were similar. CONCLUSIONS: No difference in risk of ADEs including AKI was seen with cefepime PI in pediatric CF patients. Clinical outcomes were not significantly different between groups, but sample size may have limited comparison. PI cefepime may be considered in pediatric CF patients to optimize pharmacodynamics.

A clinician survey of use assessment, documentation, and education about cannabis in persons with cystic fibrosis.

INTRODUCTION: To help open the clinician dialogue regarding cannabis use in persons with cystic fibrosis (CF) in the United States, we aimed to describe current practices of use assessment and documentation processes related to cannabis. METHODS: A cross-sectional, anonymous survey study was distributed via email to CF directors and coordinators and to the Cystic Fibrosis Foundation (CFF) listservs of nurse, pharmacist, dietitian, social worker, and psychology care team members. The survey tool included multiple choice, scaled, and open-ended items, which assessed participants' awareness of current cannabis laws in their state, prescribing practices for medical marijuana, screening and documentation practices, knowledge of and what indications participants believe cannabis and cannabidiol (CBD) could be beneficial. Data were analyzed using descriptive statistics. RESULTS: There were 282 survey participants, with majority as providers (28%) and social workers (29%), representing all US regions. Participants varied in terms of frequency of evaluating cannabis use, with 15.4% "always," 48.4% "sometimes," and 41% "rarely," or "never" asking about it. Regarding recreational versus medical cannabis use, 55.4% and 62.5% reported documentation of each type in the medical record, respectively. Participants reported appetite, pain, and nausea as the top three advocated indications for use. About 35% and 72% of participants felt "slightly" or "not at all" prepared to answer patient/family questions about cannabis and CBD, respectively. CONCLUSIONS: The approach to cannabis use assessment, documentation, and education across CF care centers is variable. There is a need for care team and patient/caregiver education materials about cannabis/CBD and CF.

Impact of a pharmacy technician and pharmacist on time to inhaled tobramycin therapy in a pediatric cystic fibrosis clinic.

BACKGROUND: Cystic fibrosis (CF) patients who grow Pseudomonas aeruginosa on respiratory culture are commonly prescribed inhaled tobramycin (TIS) to eradicate the organism. The objective of this study was to determine the impact of a pharmacy technician/pharmacist team, in conjunction with an integrated health-system specialty pharmacy (IHSSP), on the time from positive culture to prescribing and access to TIS in a pediatric CF clinic. METHODS: A retrospective study of CF patients positive for P. aeruginosa who were prescribed TIS for eradication. RESULTS: The study included 20 patients in the pregroup and 42 patients in the postgroup. Total median (interquartile range) days from positive culture to TIS being shipped to the patient from the pharmacy was significantly different: 15 (10.25-21) days in the pregroup and 9 (7-14) days in the post groups (p = .005). The time from positive culture to TIS prescribing was significantly different: 6 (5-12.75) days in the pregroup and 5 (3.75-6) days in the postgroup (p = .01). In the postgroup median time from prescription to the patient receiving the TIS was significantly different between the two groups 2 (2-5) days IHSSP group versus 6 (3-9) external specialty pharmacy group (p = .003). Time from prescription to prior authorization approval was the same in both groups. CONCLUSIONS: The addition of the pharmacy team reduced time from culture to TIS being received by the patient. Patients able to fill at the IHSSP received their medication sooner than an external specialty pharmacy. The study shows the benefit of an integrated pharmacy model in conjunction with an IHSSP.

Effects of CFTR modulators on pharmacokinetics of tobramycin during acute pulmonary exacerbations in the pediatric cystic fibrosis population.

BACKGROUND: Individuals with cystic fibrosis (CF) require higher dosages of aminoglycosides due to an increased volume of distribution (Vd ) and clearance. Optimal dosing of aminoglycosides in the CF population is essential as repeated exposure to aminoglycosides during acute pulmonary exacerbations increases risk of nephrotoxicity and ototoxicity. To date, no studies have evaluated whether chronic cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy affects pharmacokinetics of aminoglycoside antibiotics in patients with CF. The objective of this study was to determine if the addition of a CFTR modulator affects elimination rate (Ke ) for intravenously administered tobramycin in the pediatric CF population. METHODS: This retrospective study included patients aged 2 to 18 years with CF receiving chronic therapy with a CFTR modulator. Patients included had an admission both pre- and post-chronic CFTR modulator therapy during which they received therapy with IV tobramycin. RESULTS: Thirty-four patients were included in the study. The median time between pre- and post-modulator admissions was 16.5 (13.8) months. Duration of CFTR modulator therapy before post-modulator admission was a median of 8 (10.3) months. There was no significant difference in Ke (hr-1 ) between pre- and post-modulator therapy, 0.41 (0.21) pre and 0.39 (0.09) post (P = .5). Vd and peak concentration were similar between both groups. There was no difference in nephrotoxicity as defined by the pRIFLE criteria (P = .25). CONCLUSIONS: The pharmacokinetic parameters of intravenously administered tobramycin during admission for acute pulmonary exacerbation do not appear to change significantly after initiating chronic therapy with a CFTR modulator. Empiric dose adjustments for patients on CFTR modulators are not recommended.

Pharmacokinetics of Telavancin in Adult Patients with Cystic Fibrosis during Acute Pulmonary Exacerbation.

Adults with cystic fibrosis (CF) frequently harbor Staphylococcus aureus, which is increasingly antibiotic resistant. Telavancin is a once-daily rapidly bactericidal antibiotic active against methicillin-, linezolid-, and ceftaroline-resistant S. aureus Because CF patients experience alterations in pharmacokinetics, the optimal dose of telavancin in this population is unknown. Adult CF patients (n = 18) admitted for exacerbations received 3 doses of telavancin 7.5 mg/kg of body weight (first 6 patients) or 10 mg/kg (final 12 patients) every 24 h (q24h). Population pharmacokinetic models with and without covariates were fitted using the nonparametric adaptive grid algorithm in Pmetrics. The final model was used to perform 5,000-patient Monte Carlo simulations for multiple telavancin doses. The best fit was a 2-compartment model describing the volume of distribution of the central compartment (Vc ) as a multiple of total body weight (TBW) and the volume of distribution of the central compartment scaled to total body weight (Vθ) normalized by the median observed value (Vc = Vθ × TBW/52.1) and total body clearance (CL) as a linear function of creatinine clearance (CRCL) (CL = CLNR + CLθ × CRCL), where CLNR represents nonrenal clearance and CLθ represents the slope term on CRCL to estimate renal clearance. The mean population parameters were as follows: Vθ, 4.92 ± 0.76 liters · kg-1; CLNR, 0.59 ± 0.30 liters · h-1; CLθ, 5.97 × 10-3 ± 1.24 × 10-3; Vp (volume of the peripheral compartment), 3.77 ± 1.41 liters; Q (intercompartmental clearance), 4.08 ± 2.17 liters · h-1 The free area under the concentration-time curve (fAUC) values for 7.5 and 10 mg/kg were 30 ± 4.6 and 52 ± 12 mg · h/liter, respectively. Doses of 7.5 mg/kg and 10 mg/kg achieved 76.5% and 100% probability of target attainment (PTA) at a fAUC/MIC threshold of >215, respectively, for MIC of ≤0.12 mg/liter. The probabilities of reaching the acute kidney injury (AKI) threshold AUC (763 mg · h · liter-1) for these doses were 0% and 0.96%, respectively. No serious adverse events occurred. Telavancin 10 mg/kg yielded optimal PTA and minimal risk of AKI, suggesting that this FDA-approved dose is appropriate to treat acute pulmonary exacerbations in CF adults. (The clinical trial discussed in this study has been registered at ClinicalTrials.gov under identifier NCT03172793.).

Pharmacokinetic considerations in pediatric pharmacotherapy.

PURPOSE: The changes in physiological functions as children grow and organ systems mature result in pharmacokinetic alterations throughout childhood. These alterations in children result in absorption, distribution, metabolism, and excretion of drugs that are different from those seen in the typical adult diseased population. SUMMARY: Changes in gastrointestinal motility and gastric pH in neonates and infants affect the absorption rate and bioavailability of drugs. Skin absorption rate and extent can be altered by different skin structures and perfusion in young children. Intramuscular and rectal absorption become less predictable in children due to erratic absorption site perfusion and other factors. Children's body compositions also differ greatly from that in adults. Water-soluble drugs distribute more extensively in newborns due to larger water content than in older children and adults. Drug elimination and excretion are also affected in pediatric population due to differences in liver and renal function. Immature enzyme development and renal function result in reduced clearance of drugs in young children. There are limited pharmacokinetic data available for many drugs used in children. CONCLUSION: Considering the changes in pharmacokinetics in children can help pharmacists optimize the dosing and monitoring of drugs and do the best they can to help this vulnerable population.

Meropenem time above the MIC exposure is predictive of response in cystic fibrosis children with acute pulmonary exacerbations.

Meropenem exposures from 15 children (8-17 years old) with cystic fibrosis (CF) acute pulmonary exacerbation were analyzed to define the pharmacodynamic threshold required for a positive response. The primary endpoint was the relative increase in forced expiratory volume in 1 s (↑FEV1) between pre- and posttreatment. Meropenem pharmacodynamic indices (fT > MIC, fAUC/MIC, fCmin/MIC) over the first 24 h were estimated for each participant based on their individual parameter estimates and the isolated pathogen with the highest meropenem MIC. Pseudomonas aeruginosa was the most common pathogen (n = 11/15). The mean ± SD ↑FEV1 was 18.8% ± 11.3% posttreatment. The mean (range) fT > MIC exposure was 63% (0-100%). An Emax model determined a significant relationship between fT > MIC and ↑FEV1 (r2 = 0.8, P < 0.0004). 65% fT > MIC was a significant predictor of response; the median (25th, 75th %) ↑FEV1 was 28.5% (22.2%, 31.7%) in those patients who achieved above 65% fT > MIC and 7.8% (1.1%, 12.6%) in those at or below 65% fT > MIC (P = 0.001). This is the first study in CF children to link meropenem exposure with a positive response as measured by ↑FEV1. Larger studies are required to confirm this exposure threshold.

Safety of intravenous tobramycin in combination with a variety of anti-pseudomonal antibiotics in children with cystic fibrosis.

OBJECTIVES: Previous studies have examined renal safety of once daily intravenous tobramycin in individuals with cystic fibrosis. This has been mainly in combination with ceftazidime in an adolescent or adult population. In this report, we describe our institutional experience of once daily intravenous tobramycin in combination with a variety of second anti-pseudomonal antibiotics in children with cystic fibrosis. METHODS: We present a retrospective review including children with cystic fibrosis, who were admitted for a pulmonary exacerbation from January 2009 to December 2011, and treated using intravenous tobramycin. A literature review of once daily intravenous aminoglycoside dosing in cystic fibrosis was performed to compare our results to existing literature. RESULTS: A total of 35 subjects were divided into once daily dosing (n = 20) versus multiple daily dosing (n = 15) groups. Mean age was 11.3 years (± 5.7) for the once daily dosing group and 13.1 years (± 4.4) for the multiple daily dosing group (p = 0.34). All subjects had normal baseline serum creatinine at admission (once daily dosing 0.49 ± 0.14 mg/dL vs multiple daily dosing 0.62 ± 0.23 mg/dL, p = 0.07). All subjects received intravenous tobramycin, and most received piperacillin-tazobactam as their second anti-pseudomonal antibiotic (once daily dosing 45% and multiple daily dosing 40%). There was no significant change in serum creatinine in either group during antibiotic treatment (once daily dosing 0.08 ± 0.12 mg/dL vs. multiple daily dosing 0.06 ± 0.10 mg/dL, p = 0.43). All subjects had significant improvement in lung function following intravenous antibiotic therapy. CONCLUSION: We show that both once daily dosing and multiple daily dosing of intravenous tobramycin in combination with a variety of second anti-pseudomonal antibiotics were safe in terms of nephrotoxicity in children with cystic fibrosis. These findings are important given existing literature mainly examines once daily tobramycin in combination with ceftazidime, a cephalosporin, and the majority of our patients were on tobramycin with piperacillin-tazobactam, an extended spectrum penicillin plus beta-lactam. This contributes new information not previously examined in a pediatric cystic fibrosis population.

Piperacillin-tazobactam versus cefepime incidence of acute kidney injury in combination with vancomycin and tobramycin in pediatric cystic fibrosis patients.

BACKGROUND: Cystic fibrosis (CF) patients often receive prolonged courses of broad spectrum antibiotics, such as piperacillin-tazobactam or cefepime in combination with vancomycin and tobramycin. The objective of this study was to determine the difference in AKI for pediatric CF patients receiving piperacillin-tazobactam or cefepime in combination with vancomycin and tobramycin. METHODS: IRB approval from a single CF center was obtained for this retrospective cohort study. Charts were evaluated from December 1, 2008 to June 30,2015. Patients were included if they had a diagnosis of CF, age 30 days to 18 years, and received intravenous vancomycin, tobramycin, and piperacillin-tazobactam or cefepime. The primary outcome was difference of AKI incidence in patients receiving piperacillin-tazobactam or cefepime, as defined by modified pediatric risk, injury, failure, loss, end stage renal disease (pRIFLE) criteria. RESULTS: Seventy-one patients were included with a median (interquartile range) age 11 years (7-16) and weight 36.2 kg (22.7-50). AKI was identified in 54.5% (18/33) of patients receiving piperacillin-tazobactam and 13.2% (5/38) of patients receiving cefepime (P ≤ 0.0001). One patient receiving piperacillin-tazobactam experienced acute renal failure. There was a slight difference in length of admission (13 vs 10 days, P = 0.042), but no difference in days to maximum SCr (6 vs 3, P = 0.127) nor FEV1 percent predicted on admission (69% vs 65%, P = 1.00). CONCLUSIONS: AKI occurred in nearly 55% of patients with piperacillin-tazobactam therapy versus 13% of patients with cefepime therapy, which suggests cefepime may be preferred in combination with vancomycin and tobramycin for pediatric CF patients.

Vancomycin Dosing and Monitoring in the Treatment of Cystic Fibrosis: Results of a National Practice Survey.

OBJECTIVES: Vancomycin is commonly used in patients with cystic fibrosis (CF) to treat acute pulmonary exacerbations, but few guidelines exist to help dose and monitor patients. The objective of this study was to assess vancomycin use and monitoring strategies at Cystic Fibrosis Foundation (CFF)-accredited centers in hopes of developing and implementing vancomycin dosing and monitoring standards. METHODS: An anonymous national cross-sectional survey of pharmacists affiliated with CFF-accredited pediatric and/or adult centers was performed by using Surveymonkey.com. The survey consisted of 3 sections: (1) CF Center Demographic Information (10 questions); 2) vancomycin use in pediatric CF patients (31 questions); and 3) vancomycin use in adult CF patients (29 questions); it was administered from March 9, 2015, to April 13, 2015. RESULTS: The survey was completed by 31/69 (45%) pharmacists and 28 (90.3%) reported using vancomycin in the pediatric population. The most common initial starting dose for pediatric patients was 15 mg/kg/dose (57.1%) and every 6 hours was the most common dosing frequency (67.9%). The most common monitoring strategy was collection of a trough concentration (92.9%) with 57.7% of pharmacist targeting a range of 15 to 20 mg/L. The most common initial starting vancomycin dose in adults with CF was 15 mg/kg/dose (61.5%), and initial frequency of every 8 hours (73.1%). The most common monitoring strategy was a trough concentration (96.2%) with 83.3% of pharmacists reporting a goal trough range of 15 to 20 mg/L. CONCLUSIONS: The most common vancomycin dosing reported was 15 to 20 mg/kg/dose every 6 hours (pediatric) and 15 to 20 mg/kg/dose every 8 to 12 hours (adults). Serum concentrations measured to meet monitoring parameters of trough concentrations of 15 to 20 mg/L, or area under the curve to minimum inhibitory concentration ratio > 400, were the same in both pediatric and adult patients.

Population Pharmacokinetics and Safety of Ceftolozane-Tazobactam in Adult Cystic Fibrosis Patients Admitted with Acute Pulmonary Exacerbation.

Ceftolozane-tazobactam has potent activity against Pseudomonas aeruginosa, a pathogen associated with cystic fibrosis (CF) acute pulmonary exacerbations (APE). Due to the rapid elimination of many antibiotics, CF patients frequently have altered pharmacokinetics. In this multicenter, open-label study, we described the population pharmacokinetics and safety of ceftolozane-tazobactam at 3 g every 8 h (q8h) in 20 adult CF patients admitted with APE. Population pharmacokinetics were determined using the nonparametric adaptive grid program in Pmetrics for R. A 5,000-patient Monte Carlo simulation was performed to determine the probability of target attainment (PTA) for the ceftolozane component at 1.5 g and 3 g of ceftolozane-tazobactam q8h across a range of MICs using a primary threshold exposure of 60% free time above the MIC (fT>MIC). In these 20 adult CF patients, ceftolozane and tazobactam concentration data were best described by 2-compartment models, and ceftolozane clearance (CL) was significantly correlated with creatinine clearance (r = 0.71, P < 0.001). These data suggest that ceftolozane and tazobactam clearance estimates in CF patients are similar to those in adults without CF (ceftolozane CF CL, 4.76 ± 1.13 liter/h; tazobactam CF CL, 20.51 ± 4.41 liter/h). However, estimates of the volume of the central compartment (Vc) were lower than those for adults without CF (ceftolozane CF Vc, 7.51 ± 2.05 liters; tazobactam CF Vc, 7.85 ± 2.66 liters). Using a threshold of 60% fT>MIC, ceftolozane-tazobactam regimens of 1.5 g and 3 g q8h should achieve PTAs of ≥90% at MICs up to 4 and 8 µg/ml, respectively. Ceftolozane-tazobactam at 3 g q8h was well tolerated. These observations support additional studies of ceftolozane-tazobactam for Pseudomonas aeruginosa APE in CF patients. (This study has been registered at ClinicalTrials.gov under identifier NCT02421120.).

Tobramycin and Beta-Lactam Antibiotic Use in Cystic Fibrosis Exacerbations: A Pharmacist Approach.

OBJECTIVES: Survey suggests that recommended doses and dosage regimens for antipseudomonal antibiotics for the treatment of acute pulmonary exacerbations in cystic fibrosis (CF) patients are not used, and one way to address these disparities is the involvement of pharmacists who are dedicated to CF. This is the first survey specifically designed for pharmacists at Cystic Fibrosis Foundation (CFF)-accredited centers to identify how tobramycin and antipseudomonal beta-lactams are being used. The purpose of this survey is to quantify this information and to promote future study to allow for implementation of tobramycin and beta-lactam dosage and monitoring standardization. METHODS: An anonymous national cross-sectional survey of pharmacists that are affliated with CFF-accredited programs was performed using Qualtrics.com. RESULTS: The survey had a 48.5% response rate. Most pediatric pharmacists (78.6%) report using extended-interval tobramycin dosage. The most common reported starting dosage was 10 mg/kg every 24 hours; most centers aim for a maximum serum concentration (Cmax) between 20 and 40 mg/L (78.6%). A total of 26 adult pharmacists reported using extended-interval dosage (96%), using an initial dosage of 10 mg/kg/day. The most common parameters used to adjust dosage were Cmax and area under the curve (AUC; 31%); the Cmax goal was 20 to 40 mg/L (84.2%). Most respondents (79%) report using beta-lactams in combination with tobramycin. Extended-infusion and continuous-infusion beta-lactams were used more in adults than pediatric patients. CONCLUSIONS: Most CF pharmacists report using extended-interval tobramycin. With the information from this survey, the establishment of future consensus recommendations by pharmacists for optimal and consistent tobramycin and antipseudomonal beta-lactam dosage and monitoring strategies needs to be considered.

Population pharmacokinetics of meropenem administered as a prolonged infusion in children with cystic fibrosis.

OBJECTIVES: Meropenem is frequently used to treat pulmonary exacerbations in children with cystic fibrosis (CF) in the USA. Prolonged-infusion meropenem improves the time that free drug concentrations remain above the MIC (fT> MIC) in adults, but data in CF children are sparse. We describe the population pharmacokinetics, tolerability and treatment burden of prolonged-infusion meropenem in CF children. METHODS: Thirty children aged 6-17 years with a pulmonary exacerbation received 40 mg/kg meropenem every 8 h; each dose was administered as a 3 h infusion. Pharmacokinetics were determined using population methods in Pmetrics. Monte Carlo simulation was employed to compare 0.5 with 3 h infusions to estimate the probability of pharmacodynamic target attainment (PTA) at 40% fT> MIC. NCT#01429259. RESULTS: A two-compartment model fitted the data best with clearance and volume predicted by body weight. Clearance and volume of the central compartment were 0.41 ±â€Š0.23 L/h/kg and 0.30 ±â€Š0.17 L/kg, respectively. Half-life was 1.11 ±â€Š0.38 h. At MICs of 1, 2 and 4 mg/L, PTAs for the 0.5 h infusion were 87.6%, 70.1% and 35.4%, respectively. The prolonged infusion increased PTAs to >99% for these MICs and achieved 82.8% at 8 mg/L. Of the 30 children, 18 (60%) completed treatment with prolonged infusion; 5 did so at home without any reported burden. Nine patients were changed to a 0.5 h infusion when discharged home. CONCLUSIONS: In these CF children, meropenem clearance was greater compared with published values from non-CF children. Prolonged infusion provided an exposure benefit against pathogens with MICs ≥1 mg/L, was well tolerated and was feasible to administer in the hospital and home settings, the latter depending on perception and family schedule.

Microbiological activity of ceftolozane/tazobactam, ceftazidime, meropenem, and piperacillin/tazobactam against Pseudomonas aeruginosa isolated from children with cystic fibrosis.

The activity of ceftolozane/tazobactam was tested against 50 nonduplicate Pseudomonas aeruginosa from 18 cystic fibrosis children collected in 2012-2014. These isolates were multidrug resistant with susceptibility to meropenem, ceftazidime, and piperacillin/tazobactam of 46%, 58%, and 50%, respectively. Ceftolozane/tazobactam was the most active with MIC50, MIC90, and percent susceptibility of 2mg/L, 8 mg/L, and 86%.

CFTR Modulators for the Treatment of Cystic Fibrosis.

Defects in a single gene lead to the defective proteins that cause cystic fibrosis, making the disease an ideal candidate for mutation-targeted therapy. Although ivacaftor is currently the only FDA-approved CFTR modifier, others are in development.

Prevalence of depression and antidepressant therapy use in a pediatric cystic fibrosis population.

BACKGROUND: Depression is associated with significant morbidity and mortality. In recent years reports of depression in cystic fibrosis (CF) patients of all ages have increased. As awareness of depression in CF increases, there remains limited data regarding the prevalence and management of depression in the pediatric CF population. OBJECTIVES: To assess the prevalence of depression, describe depression treatment regimens, and identify risk factors for depression in the pediatric CF population at a single care center. METHODS: A retrospective chart review was conducted on 190 patients at 1 accredited CF center. Patient demographics and clinical characteristics were collected and compared between patients with depression and patients without depression. In addition, the treatment strategies of patients with depression were recorded. RESULTS: The number of patients with a documented diagnosis of depression was found to be 9%, and 50% of these patients were prescribed antidepressant therapy. The most common class of medication prescribed for depression in these patients was the selective serotonin reuptake inhibitors, where fluoxetine was the most common medication. Patients with depression had a lower mean absolute forced expiratory volume in 1 s (1.88 vs 2.48 L; P = .042), more than 5 total hospitalizations per year (4 vs 1; P = .012), and more outpatient CF exacerbations requiring treatment (1.5 vs 0; P = .023) per year than patients without depression. CONCLUSION: Identified risk factors may be used to increase depression screening of CF pediatric patients, allowing for early detection and screening in this potentially high-risk patient population. More studies are needed to determine efficacious treatment for depression in pediatric CF patients.