Dosing and Safety of Off-label Use of Caffeine Citrate in Premature Infants

The associations between caffeine treatment and common preterm morbidities: a retrospective cohort analysis

Introduction

Caffeine is one of the most used drugs in the neonatal intensive care units (NICUs). It is widely regarded as beneficial in preventing many morbidities by reducing apnea of prematurity and improving respiratory functions.

Methods

Premature infants with gestational ages >25 and <32 weeks who were hospitalized in the NICU between 2008 and 2013 and survived up to discharge were retrospectively analyzed. Infants treated with prophylactic caffeine were compared with historical controls born in 2008 and did not receive caffeine treatment. Maternal and neonatal characteristics and common neonatal morbidities were recorded.

Results

A total of 475 patients were analyzed. The patients receiving caffeine were classified as Group 1 (n = 355), and the patients not receiving caffeine were classified as Group 2 (n = 120). Despite the higher incidence of respiratory distress syndrome requiring surfactant therapy and a longer duration of respiratory support in Group 2, the rates of bronchopulmonary dysplasia (BPD) and most other common morbidities were quite comparable. The frequency of apnea was statistically lower in the group that received caffeine prophylaxis (p < 0.01).

Conclusion

In this retrospective cohort analysis, we found that caffeine prophylaxis significantly decreased apnea attacks however does not prevent respiratory morbidity such as BPD.

Caffeine dosing in premature neonates: impact of birth weight on a pharmacokinetic simulation study

BACKGROUND

The optimal caffeine dosing in extremely premature neonates remains elusive. This study aimed to evaluate the impact of birth weight on caffeine pharmacokinetics and various dosing regimens.

METHODS

In this pharmacokinetic simulation study, we generated the body weights (0-49 days of postnatal age [PNA]) of neonates <28 weeks gestational age with different birth weights (550, 750, and 1050 g). Their pharmacokinetic parameters were determined based on published pharmacokinetic models. Then, we simulated and compared the caffeine base concentration-time profiles of standard versus off-label caffeine citrate dose regimens.

RESULTS

The half-life decreased and the weight-adjusted clearance increased more significantly in neonates with lower birth weights, resulting in lower caffeine plasma concentrations. The neonate with the lowest birth weight did not achieve a threshold trough concentration of 15 mg/L after receiving the standard dose (5 mg/kg/day), while the higher-birth-weights (≥750 g) had trough concentrations below the threshold around the second week of life. Higher caffeine doses (10 mg/kg/day) resulted in peak concentrations of <36 mg/L by 10-14 days of PNA while maintaining trough concentrations above 15 mg/L throughout the 49 days PNA.

CONCLUSION

Higher-than-standard caffeine dosing may be needed for extremely premature neonates, especially for those with lower birth weights.

IMPACT

Extremely premature neonates with a lower birth weight may require a higher weight-based caffeine dosing due to their higher weight-adjusted clearance and shorter half-lives. Not only do these extremely premature neonates have a higher risk of developing bronchopulmonary dysplasia due to their structurally underdeveloped lungs, but the low birth weight-related underdosing may further contribute to the reduced caffeine effectiveness. Higher-than-standard caffeine citrate dosing (e.g., 10 mg/kg/day maintenance dose) may be needed to further prevent bronchopulmonary dysplasia.

Current Aspects of Pediatric Pharmacokinetics and Pharmacodynamics of Antimicrobials in Japan: Importance of the Promotion of Population PK/PD Analysis

Pharmacologic knowledge is important for pediatricians conducting feasible pharmacokinetic or pharmacodynamic (PK/PD) studies or applying effective antimicrobial therapies in children. Because of the difficulties in conducting PK/PD studies in children, antimicrobial PK/PD data in children are still limited. To fill in the lack of knowledge, promotion of population PK/PD analysis, which allows us to handle sparse sampling data from individual patients, is important because it is considered a suitable methodology to conduct PK/PD studies in children with limited blood drug concentration data for PK/PD analysis. Population PK/PD analysis is also useful in the clinical setting to provide individualized optimal dosage for each patient with various conditions. Here we summarized the current aspects of pediatric PK/PD studies of antimicrobials in Japan from clinical and research perspectives, specifically focusing on the importance of population PK/PD analysis.

A survey of barriers and facilitators to caffeine use for apnoea of prematurity in low- and middle-income countries

BACKGROUND

Despite its associated benefits which include better long-term pulmonary and neurodevelopmental outcome, the use of caffeine for apnoea of prematurity (AoP) has been limited in low- and middle-income countries (LMIC).

AIM

To better understand current caffeine use, the barriers and facilitators to its use and perceptions and practices in LMIC which have a disproportionately high burden of prematurity.

METHODS

An anonymous online global survey was conducted, targeting healthcare providers working and training in paediatrics and/or neonatology in LMIC.

RESULTS

A total of 181 respondents in 16 LMIC were included in the analysis; most were physicians working in publicly-funded urban tertiary hospitals. Most had received training in the use of caffeine for AoP (77%), reported expertise (70%) and confidence (96%) in its use, and had access to caffeine (65%). Caffeine availability was reported to be the greatest barrier (48%) and the greatest facilitator (37%). Other common barriers included cost (31%), access (7%) and policies or guidelines on caffeine use (7%); other common facilitators included policies or guidelines on caffeine use (11%), access (10%), staff/other providers' acceptance of caffeine as an appropriate treatment (9%) and the availability of staff to administer caffeine (8%). Most (79%) noted that access to caffeine was important, 92% agreed that caffeine improves quality of care, and 95% agreed that caffeine improves patient outcome.

CONCLUSION

Improving availability and access to low-cost caffeine will be key to increasing caffeine use in LMIC.

ABBREVIATIONS

AoP: Apnoea of Prematurity; LMIC: low- and middle-Income countries; REDCap: Research Electronic Data Capture.

Pharmacotherapy in Bronchopulmonary Dysplasia: What Is the Evidence?

Bronchopulmonary Dysplasia (BPD) is a multifactorial disease affecting over 35% of extremely preterm infants born each year. Despite the advances made in understanding the pathogenesis of this disease over the last five decades, BPD remains one of the major causes of morbidity and mortality in this population, and the incidence of the disease increases with decreasing gestational age. As inflammation is one of the key drivers in the pathogenesis, it has been targeted by majority of pharmacological and non-pharmacological methods to prevent BPD. Most extremely premature infants receive a myriad of medications during their stay in the neonatal intensive care unit in an effort to prevent or manage BPD, with corticosteroids, caffeine, and diuretics being the most commonly used medications. However, there is no consensus regarding their use and benefits in this population. This review summarizes the available literature regarding these medications and aims to provide neonatologists and neonatal providers with evidence-based recommendations.

Respiratory management for extremely premature infants born at 22 to 23 weeks of gestation in proactive centers in Sweden, Japan, and USA

Survival of preterm newborn infants have increased steadily since the introduction of surfactant treatment and antenatal steroids. In the absence of randomized controlled trials on ventilatory strategies in extremely preterm infants, we present ventilatory strategies applied during the initial phase and the continued ventilatory care as applied in three centers with proactive prenatal and postnatal management and well documented good outcomes in terms of mortality and morbidity in this cohort of infants.

Caffeine Therapy for Apnea of Prematurity: Role of the Circadian CLOCK Gene Polymorphism

Standard-dose caffeine citrate has been routinely prescribed for apnea of prematurity (AOP) management; however, some preterm infants respond well to the therapy while others do not. The AOP phenotype has been attributed solely to the immature control of the respiratory system consequent to preterm birth, but there are also important genetic influences. Based on our previous report, we tested the hypothesis that the human circadian locomotor output cycles kaput (CLOCK) gene polymorphisms play a role in the response to caffeine citrate therapy in preterm infants. We also studied the interactions of the circadian clock with aryl hydrocarbon receptor (AHR) signaling pathways in preterm babies who received caffeine citrate. This single-center study collected data from 112 preterm infants (<35 weeks gestational age) between July 2017 and July 2018, including apnea-free (n = 48) and apneic (n = 64) groups. Eighty-eight candidate single nucleotide polymorphisms (SNPs) were tested using the MassARRAY system. Association analysis was performed using the PLINK Whole Genome Data Analysis Toolset and SNPStats software. Linkage disequilibrium (LD) and haplotype analyses were performed using Hapview software. No significant intergroup differences in allele distributions or genotype frequencies of CYP1A2, CYP3A4, CYP3A5, and CYP3A7 were detected in our study on preterm babies. Two more SNPs in AHR were found to be associated with determining the response to caffeine citrate therapy in our pediatric patients. Of the 46 candidate SNPs in the CLOCK gene, 26 were found to be associated with determining the response to caffeine treatment in these babies. Interestingly, a significant association was retained for 18 SNPs in the CLOCK gene after false discovery rate correction. Moreover, strong LD formed in those variants in AHR, ADORA2A, and CLOCK genes was confirmed to be significantly associated with a better response to standard-dose caffeine therapy. In summary, CLOCK gene polymorphisms play a role in determining the response to caffeine therapy in premature neonates with AOP. However, whether the AHR and CLOCK signaling pathways crosstalk with each other during caffeine treatment remains largely unclear. Future clinical studies including more immature babies and basic research are needed to explore the mechanism by which circadian rhythms affect the response to caffeine therapy.

Evaluation of the Use of Caffeine Citrate Maintenance Doses >5 mg/kg/day in Preterm Neonates for Apnea of Prematurity

OBJECTIVE

Caffeine citrate doses >5 mg/kg/day are frequently used for apnea of prematurity. The primary objective was identification of patients maintained on 5 mg/kg/day (Group 1). Secondary objectives included identification of patients requiring dose increases: 7.5 mg/kg every 24 hours (Group 2), 10 mg/kg every 24 hours (Group 3), and 5 mg/kg every 12 hours (Group 4); comparison of demographics and clinical characteristics; and identification of patients requiring dose adjustments owing to caffeine-associated tachycardia.

METHODS

Retrospective study of neonates born between 23 to <31 weeks' gestation, receiving caffeine between January 1, 2015, and July 31, 2019. Patients receiving caffeine <1 week, initial maintenance dose >5 mg/kg/day, or with congenital abnormalities were excluded. Descriptive and inferential statistics were performed, with a p < 0.05.

RESULTS

Overall, 281 patients were included, with 99 (35.2%) in Group 1; 56 (19.9%) in Group 2; 47 (16.7%) in Group 3; and 79 (28.1%) in Group 4. Significant differences in gestational age were noted, with Group 3 and 4 patients being more premature than Groups 1 and 2 (p < 0.001). Dose increases occurred at a median postnatal age and postmenstrual age of 13.0 days and 31.4 weeks in Group 2; 17.0 days and 30.3 weeks in Group 3; and 16.0 days and 30.1 weeks in Group 4. Significant differences were noted for development of tachycardia requiring dose adjustment, with Groups 3 and 4 having the highest percentage (p < 0.001).

CONCLUSIONS

Two-thirds received caffeine citrate doses >5 mg/kg/day, with 44% receiving 10 mg/kg/day. Further exploration is necessary to determine the optimal PNA or PMA for dose adjustments.

Effects of Caffeine on Splanchnic Oxygenation in Preterm Infants

OBJECTIVE

The aim of this study is to assess the effects of administering 20 mg/kg loading dose of caffeine citrate intravenously on splanchnic oxygenation in preterm infants.

STUDY DESIGN

The infants with a gestational age (GA) of <34 weeks who were administered with a 20 mg/kg intravenous loading dose of caffeine citrate within 48 hours after birth were investigated prospectively. Regional splanchnic oxygen saturation (rsSO₂) and splanchnic fractional tissue oxygen extraction rate (sFTOE) were measured using near-infrared spectroscopy before caffeine infusion, immediately after caffeine infusion and 1, 2, 3, 4, and 6 hours (h) after dose completion; postdose values were compared with predose values.

RESULTS

A total of 41 infants with a mean GA of 29.2 ± 1.6 weeks and birth weight of 1,315 ± 257 g as well as postnatal age of 32.2 ± 10.8 hours were included in the study. rsSO₂ significantly reduced from 63.1 to 57.5% immediately after caffeine infusion, 55.1% after 1 hour, and 55.2% after 2 hours with partial recovery at 3-hour postdose. sFTOE increased correspondingly.

CONCLUSION

Caffeine reduces splanchnic oxygenation and increases splanchnic oxygen extraction for at least 2 hours with partial recovery to predose levels at 3-hour postdose.

Therapy for Apnoea of Prematurity: A Retrospective Study on Effects of Standard Dose and Genetic Variability on Clinical Response to Caffeine Citrate in Chinese Preterm Infants

INTRODUCTION

Apnoea of prematurity (AOP) is among the most common diagnoses in the neonatal intensive care unit. Caffeine treatment is a preferred treatment choice. However, neonatal caffeine therapy results in significant intersubject variability. This study aimed to determine the effects of plasma caffeine levels based on standard dose and genetic variability on clinical response to caffeine citrate in Chinese preterm infants.

METHODS

This single-center and retrospective study examined data from 112 preterm infants (< 35 weeks gestational age) between July 2017 and July 2018. Subjects were divided into apnoea-free (n = 48) and apnoeic (n = 64) groups, and their clinical outcomes were summarized. Liquid chromatography-tandem mass spectrometry was used to measure levels of caffeine and its primary metabolites. Eighty-eight single-nucleotide polymorphisms were chosen for genotyping by a MassARRAY system.

RESULTS

Preterm infants in the apnoea-free group were associated with a reduction in the incidence of bronchopulmonary dysplasia and a reduced requirement for patent ductus arteriosus ligation. No significant association was observed between plasma-trough-concentration-to-dose (C₀/D) ratio and birth weight, gestational age, or postnatal age in either group. Polymorphisms in CYP1A2 and aryl hydrocarbon receptor (AHR) genes did not affect plasma caffeine levels. Polymorphisms in adenosine receptor genes ADORA1 (rs10920568 and rs12744240), ADORA2A (rs34923252 and rs5996696), and ADORA3 (rs10776727 and rs2298191), especially in AHR (rs4410790) and adenosine deaminase (rs521704), play critical roles in the interindividual response to caffeine therapy.

CONCLUSIONS

Genetic polymorphisms in caffeine's target receptors, but not the exposure levels based on the standard dosing, were associated with variable responses to caffeine therapy in preterm neonates. Future studies are needed to uncover how these genetic variants affect responses to caffeine therapy in this patient population.

Immature control of breathing and apnea of prematurity: the known and unknown

This narrative review provides a broad perspective on immature control of breathing, which is universal in infants born premature. The degree of immaturity and severity of clinical symptoms are inversely correlated with gestational age. This immaturity presents as prolonged apneas with associated bradycardia or desaturation, or brief respiratory pauses, periodic breathing, and intermittent hypoxia. These manifestations are encompassed within the clinical diagnosis of apnea of prematurity, but there is no consensus on minimum criteria required for diagnosis. Common treatment strategies include caffeine and noninvasive respiratory support, but other therapies have also been advocated with varying effectiveness. There is considerable variability in when and how to initiate and discontinue treatment. There are significant knowledge gaps regarding effective strategies to quantify the severity of clinical manifestations of immature breathing, which prevent us from better understanding the long-term potential adverse outcomes, including neurodevelopment and sudden unexpected infant death.

Population pharmacokinetic study of caffeine citrate in Chinese premature infants with apnea

WHAT IS KNOWN AND OBJECTIVES

Caffeine citrate is a commonly used methylxanthine for pharmacologic treatment of apnea of prematurity. The aim of this study was to develop and verify a population pharmacokinetic (PPK) model, which can provide a reference for individualized caffeine citrate treatment of apnea in Chinese premature infants.

METHODS

A total of 88 serum concentration measurements from 46 preterm patients (median gestational age 29 weeks) were retrospectively collected and the relevant clinical data of patients were recorded. The PPK analysis was performed by non-linear mixed-effect modelling method using NONMEM. Allometric scaling was applied in the PPK analysis, and the final model was evaluated by graphic and statistical methods, including goodness-of-fit plots, normalized prediction distribution errors plots and bootstrap procedures.

RESULTS

A one-compartment model with first-order elimination was successfully fitted to the data. The typical scaled values for the parameters clearance and volume of distribution (V) were 0.268 L/h and 109 L per 70 kg, respectively. The weight at the time of blood collection (CW) and post-natal age were identified as important predictors for pharmacokinetic parameters of caffeine. The evaluation process showed good stability and predictability of the final PPK model.

WHAT IS NEW AND CONCLUSION

This is a complete PPK study of caffeine citrate in Chinese premature infants with apnea, which complements caffeine pharmacokinetic data of the premature from China. A final PPK model was developed which may serve as a beneficial tool for the use of caffeine citrate in the treatment of apnea in Chinese preterm infants.