Allergy to beta-lactam antibiotics in children: predictors for a positive oral challenge test.

OBJECTIVE: Beta-lactam antibiotic allergies are reported in 5%-10% of children; however, up to 90% do not have any reaction at oral challenge test (OCT). This study aimed to determine the frequency and identify predictors of positive in-hospital graded beta-lactam OCTs in children with a beta-lactam antibiotic allergy label (AAL). DESIGN: This is a retrospective study conducted over 7 years, including children aged 0-19 years who underwent a beta-lactam OCT. The OCT comprised an in-hospital graded challenge followed by a 5-day outpatient antibiotic course. Univariate and multivariate logistic regression analyses were performed to identify predictors of a positive in-hospital graded OCT. RESULTS: Overall, 1259 beta-lactam OCTs were included: median age at time of OCT was 6.3 years (range 8.8 months to 19.2 years). Of these, 18 (1.4%) in-hospital graded OCTs were positive and 10 (0.8%) were equivocal, with only 4 children (0.3%) having an immediate, severe reaction to their in-hospital graded OCT. Factors associated with a positive in-hospital graded OCT on univariate analysis were: history of other drug allergy (OR 2.7, 95% CI 1.0 to 7.2; p 0.05), an index reaction which was severe (OR 2.9, 95% CI 1.1 to 7.6; p 0.035), immediate and severe (OR 5.85, 95% CI 1.7 to 20.0; p 0.005) or that required epinephrine (OR 9.65, 95% CI 1.7 to 53.6; p 0.01). CONCLUSION: Of the children referred with a beta-lactam AAL, only 1.4% had a positive in-hospital graded OCT. Risk factors for a positive in-hospital graded OCT were history of other drug allergy, an index reaction which was severe, immediate and severe or required epinephrine.

Variation in clinical practice guideline recommendations for medication use in pregnancy in Australia: A systematic review.

BACKGROUND: Medication use in pregnancy is common; however, it is unknown if clinical practice guideline (CPG) prescribing recommendations referred to in Australia at the state, national and international level are consistent. AIMS: This systematic review aimed to: (1) identify sources of CPGs that inform prescribing during pregnancy in Australia; (2) assess CPG quality; and (3) evaluate variation within CPG recommendations for medication use in three common conditions in pregnancy: prophylactic antibiotics following premature rupture of membranes (PROM) at term, antidepressants in pregnancy and metformin in gestational diabetes mellitus (GDM). MATERIALS AND METHODS: A literature search was conducted across PubMed, Scopus and EMBASE databases. Grey literature was identified through publicly available Australian policy statements. Prescribing recommendations for prophylactic antibiotics following PROM at term, antidepressants in pregnancy and metformin in GDM, were compared at the state, national and international levels. CPG quality was assessed using the Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument. RESULTS: We identified 39 CPG sources that inform prescribing during pregnancy in Australia. CPG quality varied between resources. There was minor variation in recommendations for antibiotic prophylaxis in PROM at term. Recommendations regarding metformin use in GDM were also variable, with CPGs either recommending its use as a first-line agent when lifestyle modifications are not effective or when insulin therapy is not practicable. Recommendations for antidepressant use were consistent across CPGs analysed. CONCLUSION: Multiple CPGs exist to inform prescribing during pregnancy in Australia, with variation present within CPG quality and recommendations. These findings offer insight into potential sources of variation in maternal and neonatal health outcomes.

The Australian evidence-based clinical practice guideline for attention deficit hyperactivity disorder.

OBJECTIVE: The objective of this article was to provide an overview of the development and recommendations from the Australian evidence-based clinical practice guideline for attention deficit hyperactivity disorder (ADHD). The guideline aims to promote accurate and timely identification and diagnosis, and optimal and consistent treatment of ADHD. METHODS: Development integrated the best available evidence with multidisciplinary clinical expertise and the preferences of those with lived experience, underpinned by the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework. The 23 guideline development group members included psychiatrists, paediatricians, general practitioners, psychologists, speech pathologists, occupational therapists, educators, Indigenous psychologists, and people with a lived experience; with two independent chairs and a methodologist. Where appropriate, evidence reviews from the National Institute for Health and Care Excellence (NICE) 2018 'Attention Deficit Hyperactivity Disorder: Diagnosis and Management' guideline were updated. Fifty prioritised clinical questions were addressed in 14 systematic reviews (new and updated from NICE 2018) and 28 narrative reviews. RESULTS: The 113 clinical recommendations apply to young children (5 years and under), children, adolescents and adults. They provide guidance for clinicians on identification, screening, diagnosis, multimodal treatment and support, including pharmacological and non-pharmacological interventions. The guideline and supporting information are available online: https://adhdguideline.aadpa.com.au/. CONCLUSIONS: The guideline was approved by the National Health and Medical Research Council (NHMRC) of Australia and relevant medical and allied health professional associations. It is anticipated that successful implementation and uptake of the guideline by organisations, health care providers and other professionals will increase delivery of evidence-based treatment and improve health outcomes for the more than 800,000 Australians with ADHD.

Individualized vancomycin dosing in infants: prospective evaluation of an online dose calculator.

BACKGROUND: Empiric vancomycin dosing regimens fail to achieve recommended target trough concentrations of 10-20 mg/L in the majority of infants. This study assessed the performance of a model-based dosing calculator (Vanc App) in achieving target vancomycin concentrations at first steady-state level. METHODS: This was a multicenter prospective study in four tertiary pediatric hospitals over an 18-month period. Infants aged 0-90 days with suspected Gram-positive sepsis requiring empiric vancomycin treatment were included if they did not meet any of the exclusion criteria: post-menstrual age (PMA) <25 weeks, weight <500 g, glycopeptide allergy, receiving extracorporeal membrane oxygenation, vancomycin use within the previous 72 h, and renal impairment. The Vanc App used a published population pharmacokinetic model to generate a dose based on the infant's PMA, weight, creatinine, and target vancomycin concentration. RESULTS: A total of 40 infants were included; 40% were female, median (range) weight was 2505 (700-4460) g and median (range) PMA was 37.4 (25.7-49.0) weeks. The median (range) vancomycin dose was 45 (24-79) mg/kg/day. All infants had trough vancomycin concentrations measured at steady-state (24-<48 hours) and 30 (75%) infants achieved target concentrations. Five infants had supratherapeutic (median 25, range 21-38 mg/L) and five had subtherapeutic (median 6, range <5-9 mg/L) concentrations. An area under the concentration-time curve (AUC0-24) of 400-650 mg/L.h was achieved in 33 (83%) infants. There were no infusion-related reactions or nephrotoxicity. CONCLUSION: Individualized intermittent vancomycin dosing using a model-based online calculator resulted in 75% and 83% of infants achieving target trough and AUC0-24, respectively, at first steady-state level. There were no vancomycin-related nephrotoxicity or infusion-related reactions.

Timing of Live Attenuated Vaccination in Infants Exposed to Infliximab or Adalimumab in Utero: A Prospective Cohort Study in 107 Children.

BACKGROUND AND AIMS: For infants exposed in utero to anti-tumour necrosis factor-α [TNF] medications, it is advised that live-attenuated vaccinations be postponed until the drug is cleared, but little is known about time to clearance. To minimize delays before live-attenuated vaccination can be given, we aimed to develop a pharmacokinetic model to predict time-to-clearance in infants exposed during pregnancy. METHODS: We prospectively followed in utero infliximab/adalimumab-exposed infants of mothers with inflammatory bowel disease across four countries between 2011 and 2018. Infants with a detectable anti-TNF umbilical-cord level and at least one other blood sample during the first year of life were included. RESULTS: Overall, 107 infants were enrolled, including 166 blood samples from 71 infliximab-exposed infants and 77 samples from 36 adalimumab-exposed infants. Anti-TNF was detectable in 23% [n = 25] of infants at 6 months. At 12 months, adalimumab was not detected but 4% [n = 3] had detectable infliximab. A Bayesian forecasting method was developed using a one-compartment pharmacokinetic model. Model validation showed that the predicted clearing time was in accordance with the measured observations. A clinician-friendly online calculator was developed for calculating full anti-TNF clearing time: https://xiaozhu.shinyapps.io/antiTNFcalculator2/. CONCLUSIONS: Almost one-quarter of infants born to mothers receiving anti-TNF during pregnancy have detectable anti-TNF at 6 months. To limit the time to live-attenuated vaccination in infants of mothers receiving anti-TNF during pregnancy, the results of a cord drug level at birth and a second sample ≥ 1 month thereafter can be used to estimate the time for full anti-TNF clearance in these children.

Impact of antibiotic allergy labels on patient outcomes in a tertiary paediatric hospital.

AIMS: Antibiotic allergies are reported in 5-15% of children. This study aimed to evaluate the impact of common ß-lactam antibiotic allergy labels (AALs) on hospital treatment, focusing on length of stay and appropriateness of antibiotic prescribing. METHODS: This was a retrospective cohort study over 21 months at the Royal Children's Hospital Melbourne, Australia. A subset of children with the most common ß-lactam allergies, and who required admission for intravenous antibiotics over a 12-month period, was analysed for appropriateness of prescribing. Non-allergic patients were matched to evaluate associations between AALs and hospital treatment. RESULTS: There were 98 912 children admitted over the study period, of whom 938 (1%) had at least one AAL on first admission. Of all encounters, 5145 (2.5%) were for children with AALs. The most common AALs were to amoxicillin and amoxicillin-clavulanic acid combinations (40.8%), cefalexin (14.4%) and trimethoprim-sulfamethoxazole (9.7%). For the subset, there were 66 admissions for children who required intravenous antibiotics. Documentation was adequate for 27% of AALs. Inappropriate prescribing occurred in almost half (47%). Hospital stay was longer for children with AALs (median 4.7 days; IQR 2.3-9.2) compared to non-allergic controls (median 3.9 days; IQR 1.9-6.8; P = .02). Children with AALs were more likely to receive restricted antibiotics (aOR 3.03; 95% CI, 1.45-6.30; P = .003). CONCLUSION: This is the first study to demonstrate high rates of inappropriate prescribing in children with AALs. Children with AALs were significantly more likely to receive restricted antibiotics and had a longer length of stay compared with non-allergic controls.

A pilot randomised placebo-controlled trial of cannabidiol to reduce severe behavioural problems in children and adolescents with intellectual disability.

AIMS: Severe behavioural problems (SBP) are a major contributor to morbidity in children with intellectual disability (ID). Medications used to treat SBP in ID are associated with a high risk of side effects. Cannabidiol has potential therapeutic effects in SBP. This pilot study aimed to investigate the feasibility of conducting a randomised placebo-controlled trial of cannabidiol to reduce SBP in children with ID. METHODS: This is a double-blind, placebo-controlled, two-armed, parallel-design, randomised controlled trial of cannabidiol in children aged 8-16 years with ID and SBP. Participants were randomised 1:1 to receive either 98% cannabidiol in oil (Tilray, Canada) or placebo orally for 8 weeks. The dose was up-titrated over 9 days to 20 mg/kg/day in two divided doses, with a maximum dose of 500 mg twice/day. The feasibility and acceptability of all study components were assessed. RESULTS: Eight children were randomised, and all completed the full study protocol. There were no serious adverse events or drop-outs. Protocol adherence for key study components was excellent: study visits 100%, medication adherence 100%, blood tests 92% and questionnaire completion 88%. Parents reported a high degree of acceptability with the study design. All parents reported they would recommend the study to other families with children with similar problems. There was an efficacy signal in favour of active drug. CONCLUSIONS: The findings suggest that the study protocol is feasible and acceptable to patients with ID and SBP and their families.

Population pharmacokinetics of ivermectin for the treatment of scabies in Indigenous Australian children.

Ivermectin is a broad-spectrum antiparasitic agent used for the treatment and control of neglected tropical diseases. In Australia, ivermectin is primarily used for scabies and is licensed in children aged ≥5 years weighing >15 kg. However, young children, aged <5 years, are particularly vulnerable to scabies and its secondary complications. Therefore, this study aimed to determine an appropriate ivermectin dose for children aged 2 to 4 years and weighing ≤15 kg. We conducted a prospective, pharmacokinetic study of ivermectin in Indigenous Australian children aged between 5 and 15 years and weighing >15 kg. Doses of 200 µg/kg rounded to the nearest whole or half 3 mg tablet were given to children with scabies and ivermectin concentrations determined at two time points after dosing. A population pharmacokinetic model was developed using non-linear mixed effects modelling. A separate covariate database of children aged 2 to 4 years and weighing <15 kg was used to generate 1000 virtual patients and simulate the dose required to achieve equivalent drug exposure in young children as those aged ≥5 years. Overall, 26 children who had 48 ivermectin concentrations determined were included, 11 (42%) were male, the median age was 10.9 years and median body weight 37.6 kg. The final model was a two-compartment model with first-order absorption and linear elimination. For simulated children aged 2 to 4 years, a dose of 3 mg in children weighing 10-15 kg produced similar drug exposures to those >5 years. The median simulated area under the concentration-time curve was 976 µg∙h/L. Using modelling, we have identified a dosing strategy for ivermectin in children aged 2 to 4 years and weighing less than 15 kg that can be prospectively evaluated for safety and efficacy.

Protocol for a single patient therapy plan: A randomised, double-blind, placebo-controlled N-of-1 trial to assess the efficacy of cannabidiol in patients with intractable epilepsy.

AIM: This paper describes the use of the single patient therapy plan (SPTP). The SPTP has been designed to assess the efficacy at an individual level of a commercially available cannabinoid product, cannabidiol, in reducing seizure frequency in paediatric patients with intractable epilepsy. METHODS: The SPTP is a randomised, double-blind, placebo-controlled N-of-1 trial designed to assess the efficacy of treatment in a neurology outpatient setting. The primary objective of the SPTP is to assess the efficacy of cannabidiol in reducing seizure frequency in each patient with intractable epilepsy, with change in seizure frequency being the primary outcome of interest. The analysis adopts a Bayesian approach, which provides results in the form of posterior probabilities that various levels of benefit (based on the primary outcome measure, seizure frequency) have been achieved under active treatment compared to placebo, accompanied by decision rules that provide thresholds for deciding whether treatment has been successful in the individual patient. The SPTP arrangement is most accurately considered part of clinical practice rather than research, since it is aimed at making clinical treatment decisions for individual patients and is not testing a hypothesis or collecting aggregate data. Therefore, Human Research Ethics Committee approval was considered not to be required, although it is recommended that hospital Clinical Ethics Committees provide ethical oversight. CONCLUSION: These SPTP resources are made available so that they may inform clinical practice in the treatment of severe epilepsy or adapted for use in other conditions.

Does cannabidiol reduce severe behavioural problems in children with intellectual disability? Study protocol for a pilot single-site phase I/II randomised placebo controlled trial.

INTRODUCTION: Severe behavioural problems (SBPs) are a common contributor to morbidity and reduced quality of life in children with intellectual disability (ID). Current medication treatment for SBP is associated with a high risk of side effects. Innovative and safe interventions are urgently needed. Anecdotal reports and preliminary research suggest that medicinal cannabis may be effective in managing SBP in children with developmental disabilities. In particular, cannabidiol (CBD) may be a plausible and safe alternative to current medications. Families who are in urgent need of solutions are seeking cannabis for their ID children with SBP. However there is no evidence from randomised controlled trials to support the use of CBD for SBP. This pilot study aims to investigate the feasibility of conducting a randomised placebo-controlled trial of CBD to improve SBP in children with ID. METHODS AND ANALYSIS: This is a single-site, double-blind, parallel-group, randomised, placebo-controlled pilot study of 10 participants comparing 98% CBD oil with placebo in reducing SBP in children aged 8-16 years with ID. Eligible participants will be randomised 1:1 to receive either CBD 20 mg/kg/day or placebo for 8 weeks. Data will be collected regarding the feasibility and acceptability of all study components, including recruitment, drop-out rate, study visit attendance, protocol adherence and the time burden of parent questionnaires. Safety outcomes and adverse events will be recorded. All data will be reported using descriptive statistics. These data will inform the design of a full scale randomised controlled trial to evaluate the efficacy of CBD in this patient group. ETHICS AND DISSEMINATION: This protocol has received ethics approval from the Royal Children's Hospital ethics committee (Human Research Ethics Committee no. 38236). Results will be disseminated through peer-reviewed journals, professional networks, conferences and social media. TRIAL REGISTRATION NUMBER: ACTRN12618001852246.

A nationwide parent survey of antibiotic use in Australian children.

BACKGROUND: Antimicrobial resistance is increasing globally, largely due to high rates of antibiotic use and misuse. Factors that influence frequent antibiotic use in children are poorly understood. OBJECTIVES: This study describes rates of antibiotic use in Australian children and investigates parental factors including knowledge, attitudes and behaviours that influence antibiotic use. METHODS: An online questionnaire relating to antibiotic use was administered as part of the Royal Children's Hospital National Child Health Poll to a randomly recruited nationwide sample of parents or guardians of children aged 0-17 years in Australia. Data on antibiotic use in children and parental knowledge of appropriate indications for antibiotics and behaviours were collected. Standard binary logistic regression was used to assess associations between parent demographics and behaviour with antibiotic administration. RESULTS: The survey was completed by 2157 parents (64% completion rate), of which 1131 (52%) reported having given oral antibiotics to one or more of their children in the preceding 12 months. Of the 3971 children represented overall, 1719 (43%) had received at least one course of antibiotics. The average number of courses per child was 0.86 overall and 1.96 courses per child among those with reported antibiotic use. Notably, 194/1131 (17%) parents reported giving antibiotics to their child without a prescription. Poor parental knowledge of antibiotic indications was associated with antibiotic use. CONCLUSIONS: Reducing excessive use of antibiotics in children is necessary in the global strategy for preventing antimicrobial resistance. This study identified areas for public health interventions to educate parents and increase regulation of access to antibiotics.

Non-ß-Lactam Antibiotic Hypersensitivity Reactions.

OBJECTIVES: Antibiotics are among the most common prescriptions in children, and non-ß-lactam antibiotics (NBLAs) account for almost half of those prescribed in Australian pediatric hospitals. Despite this, data on NBLA hypersensitivity in children are limited. This study describes reported hypersensitivity reactions to NBLAs in children and the results of allergy evaluation. METHODS: Children with a suspected NBLA allergy who had skin testing and/or an intravenous or oral challenge test (OCT) between May 2011 and June 2018 were included. Patients were excluded if they were >18 years old or did not complete the allergy evaluation for any reason other than allergic reaction. RESULTS: Over the 7-year study period, 141 children had 150 allergy evaluations of 15 different NBLAs. The median time from the initial reported reaction to allergy evaluation was 1.9 (range 0.1-14.9) years. Overall, 27 of the 150 (18.0%) challenge tests to NBLAs had positive results, with the rate of positive OCT results being highest for trimethoprim-sulfamethoxazole (15 of 46; 32.6%) and macrolides (8 of 77; 10.4%). Although 4 children reported initial anaphylactic reactions, no patients had severe symptoms on rechallenge or required adrenaline. Of the challenges that had positive results, the majority of children (23 of 27; 85.2%) had symptoms on repeat challenge similar to those that were initially reported. CONCLUSIONS: Overall, 8 of 10 children with NBLA allergy could be delabeled. On average, patients waited 1.9 years to be rechallenged. Timely access to allergy evaluation to delabel these patients is needed to preserve first-line antibiotics.

Optimizing Mycophenolic Acid Exposure in Kidney Transplant Recipients: Time for Target Concentration Intervention.

The immunosuppressive agent mycophenolate is used extensively in kidney transplantation, yet dosing strategy applied varies markedly from fixed dosing ("one-dose-fits-all"), to mycophenolic acid (MPA) trough concentration monitoring, to dose optimization to an MPA exposure target (as area under the concentration-time curve [MPA AUC0-12]). This relates in part to inconsistent results in prospective trials of concentration-controlled dosing (CCD). In this review, the totality of evidence supporting mycophenolate CCD is examined: pharmacological characteristics, observational data linking exposure to efficacy and toxicities, and randomized controlled trials of CCD, with attention to dose optimization method and exposure achieved. Fixed dosing of mycophenolate consistently leads to underexposure associated with rejection, as well as overexposure associated with toxicities. When CCD is driven by pharmacokinetic calculation to a target concentration (target concentration intervention), MPA exposure is successfully controlled and clinical benefits are seen. There remains a need for consensus on practical aspects of mycophenolate target concentration intervention in contemporary tacrolimus-containing regimens and future research to define maintenance phase exposure targets. However, given ongoing consequences of both overimmunosuppression and underimmunosuppression in kidney transplantation, impacting short- and long-term outcomes, these should be a priority. The imprecise "one-dose-fits-all" approach should be replaced by the clinically proven MPA target concentration strategy.

Vancomycin is commonly under-dosed in critically ill children and neonates.

AIMS: Vancomycin is frequently used in critically ill children in whom the drug pharmacokinetics are significantly altered as a result of changes in renal clearance and volume of distribution. Therapeutic drug monitoring (TDM) is recommended to achieve vancomycin trough concentrations between 10 and 20 mg/L. In this study we reviewed vancomycin dosing, TDM and treatment outcomes in paediatric and neonatal intensive care unit patients. METHODS: We reviewed the medical records of all patients receiving intravenous vancomycin in a tertiary paediatric and neonatal intensive care unit over a 10-month period. Demographic, vancomycin dosing, TDM and drug-related adverse effects data were collected. RESULTS: In total, 115 children received 126 courses of vancomycin and had at least 1 TDM blood sample taken at steady state. In only 38/126 (30%) courses was the target concentration (10-20 mg/L) achieved at the initial steady state trough sample. Of the 88 courses that had initial trough concentrations outside the target range, the dose was adjusted in only 49 (56%). Overall, minimum doses of 30 mg/kg/day in neonates with a corrected gestational age of <35 weeks, and 50 mg/kg/day in older children, were required to achieve target vancomycin concentrations. Vancomycin-attributable nephrotoxicity occurred in 10/126 (8%) courses and there were no episodes of red man syndrome. CONCLUSION: In critically ill children, individualised dosing is needed. In the absence of Bayesian model-based dosing, in children with normal renal function, empiric vancomycin doses of at least 30 mg/kg/day in neonates of <35 weeks corrected gestational age, and 50 mg/kg/day in older children, should be considered. Optimisation of TDM practices through the development of protocols, ideally built into electronic medical records, should be considered.

PEBBLES study protocol: a randomised controlled trial to prevent atopic dermatitis, food allergy and sensitisation in infants with a family history of allergic disease using a skin barrier improvement strategy.

INTRODUCTION: The skin is an important barrier against environmental allergens, but infants have relatively impaired skin barrier function. There is evidence that impaired skin barrier function increases the risk of allergic sensitisation, atopic dermatitis (AD) and food allergy. We hypothesise that regular prophylactic use of emollients, particularly those that are designed to improve skin barrier structure and function, will help prevent these conditions. With the aim of determining if application of a ceramide-dominant emollient two times per day reduces the risk of AD and food allergy, we have commenced a multicentre phase III, outcome assessor blinded, randomised controlled trial of this emollient applied from birth to 6 months. METHODS AND ANALYSIS: Infants (n=760) with a family history of allergic disease will be recruited from maternity hospitals in Melbourne. The primary outcomes are as follows: the presence of AD, assessed using the UK Working Party criteria, and food allergy using food challenge, in the first 12 months of life as assessed by a blinded study outcome assessor. Secondary outcomes are as follows: food sensitisation (skin prick test), skin barrier function, AD severity, the presence of new onset AD after treatment cessation (between 6 and 12 months) and the presence of parent reported AD/eczema. Recruitment commenced in March 2018. ETHICS AND DISSEMINATION: The PEBBLES Study is approved by the Human Research Ethics Committees of the Royal Children's Hospital (RCH) (#37090A) and the Mercy Hospital for Women (2018-008). Parents or guardians will provide written informed consent. Outcomes will be disseminated through peer-reviewed publications and presented at scientific conferences. TRIAL REGISTRATION NUMBERS: ACTRN12617001380381 and NCT03667651.

Continuous Versus Intermittent Vancomycin Infusions in Infants: A Randomized Controlled Trial.

BACKGROUND: In adults, continuous infusions of vancomycin (CIV) are associated with earlier attainment of target drug concentrations, require fewer blood samples for monitoring, and may reduce drug toxicity. We aimed to determine, in young infants, if CIV or intermittent infusions of vancomycin (IIV) better achieves target vancomycin concentrations at the first steady-state level and to compare the frequency of drug-related adverse effects. METHODS: In a multicenter randomized controlled trial in 2 tertiary neonatal units over a 40-month period, young infants aged 0 to 90 days requiring vancomycin therapy for at least 48 hours were randomly assigned to CIV and IIV. RESULTS: Of 111 infants randomized, 104 were included in the intention-to-treat analysis. Baseline characteristics were similar for both groups. The proportion of infants achieving target concentrations at the first steady-state level was higher for CIV compared with IIV (45 in 53 [85%] vs 21 in 51 [41%]; P < .001). Fewer dose adjustments were required in the CIV group (median 0; range 0-1) compared with the IIV group (median 1; range 0-3; P < .001). The mean daily dose required to achieve target concentrations was lower with CIV compared with IIV (40.6 [SD 10.7] vs 60.6 [SD 53.0] mg/kg per day, respectively; P = .01). No drug-related adverse effects occurred in either group. CONCLUSIONS: In young infants, CIV is associated with earlier and improved attainment of target concentrations compared with IIV. Lower total daily doses are required to achieve target levels with CIV. There is no difference in the rate of drug-related adverse effects.