Use of methylxanthine therapies for the treatment and prevention of apnea of prematurity

Predictors for poor daily weight gain in preterm neonates exposed to different dose regimens of caffeine in ICU- a retrospective cohort study

BACKGROUND

With a wide therapeutic index, efficacy, ease of use, and other neuroprotective and respiratory benefits, caffeine citrate(CC) is currently the drug of choice for preterm neonates (PTNs). Caffeine-induced excessive energy expenditure, diuresis, natriuresis, and other CC-associated potential side-effects (CC-APSEs) result in lower daily-weight gain (WG) in premature neonates. This study aimed to evaluate the risk factors for daily-WG in neonates exposed to different dose regimens of caffeine in ICU.

METHOD

This retrospective cohort study included neonates of ≤ 36weeks gestational age (GA) and received CC-therapy. The same participants were followed for data analysis in two postnatal phases: 15-28 and 29-42 days of life (DOL). Based on daily CC-dose, formed group-I (received; standard-doses = 5 mg/kg/day), group-II (received;>5-7 mg/kg/day), and group-III (received;>7 mg/kg/day). Prenatal and postnatal clinical characteristics, CC-regimen, daily-WG, CC-APSEs, and concomitant risk-factors, including daily-caloric intake, Parenteral-Nutrition duration, steroids, diuretics, and ibuprofen exposure, were analyzed separately for group-II and group-III using group-I as standard. Regression analysis was performed to evaluate the risk factors for daily-WG.

RESULTS

Included 314 PTNs. During 15-28 DOL, the mean-daily-WG(MD-WG) was significantly higher in group-I than group-II [19.9 ± 0.70 g/kg/d vs. 17.7 ± 0.52 p = 0.036] and group-III [19.9 ± 0.70 g/kg/d vs. 16.8 ± 0.73 p < 0.001]. During 29-42 DOL the MD-WG of group-I was only significantly higher than group-III [21.7 ± 0.44 g/kg/d vs. 18.3 ± 0.41 g/kg/d p = 0.003] and comparable with group-II. During 15-28 DOL, observed CC-APSEs was significantly higher in group-II and III but during 29-42 DOL it was only significant in group-III. In the adjusted regression analysis for daily-WG during 15-28DOL, with respect to standard-dose, 5-7 mg/kg/day (β=-1.04; 95%CI:-1.62,-0.93) and > 7-10 mg/kg/day (β=-1.36; 95%CI:-1.56,-1.02) were associated with a lower daily-WG. However, during 29-42DOL, this association was present only for > 7-10 mg/kg/day (β=-1.54; 95%CI:-1.66,-1.42). The GA ≤ 27weeks (β=-1.03 95%CI:-1.24, -0.88) was associated with lower daily-WG only during 15-28DOL. During both periods of therapy, higher cumulative-caffeine dose and presence of culture proven sepsis, tachypnea, hyponatremia, and feeding intolerance were significantly associated with lower daily-WG. Conversely, daily kcal intake was found to be linked with an increase in daily-WG in both periods.

CONCLUSION

In this study cohort exposure to higher caffeine daily and cumulative doses is associated with lower postnatal daily-WG in PTNs than standard-daily doses, which may be due to its catabolic effects and CC-APSEs.

Caffeine for apnea and prevention of neurodevelopmental impairment in preterm infants: systematic review and meta-analysis

This systematic review and meta-analysis evaluated the evidence for dose and effectiveness of caffeine in preterm infants. MEDLINE, EMBASE, CINHAL Plus, CENTRAL, and trial databases were searched to July 2022 for trials randomizing preterm infants to caffeine vs. placebo/no treatment, or low (≤10 mg·kg-1) vs. high dose (>10 mg·kg-1 caffeine citrate equivalent). Two researchers extracted data and assessed risk of bias using RoB; GRADE evaluation was completed by all authors. Meta-analysis of 15 studies (3530 infants) was performed in REVMAN across four epochs: neonatal/infant (birth-1 year), early childhood (1-5 years), middle childhood (6-11 years) and adolescence (12-19 years). Caffeine reduced apnea (RR 0.59; 95%CI 0.46,0.75; very low certainty) and bronchopulmonary dysplasia (0.77; 0.69,0.86; moderate certainty), with higher doses more effective. Caffeine had no effect on neurocognitive impairment in early childhood but possible benefit on motor function in middle childhood (0.72; 0.57,0.91; moderate certainty). The optimal dose remains unknown; further long-term studies, are needed.

Dose-Response Study of Caffeine on Postnatal Weight Gain in Premature Neonates-A Retrospective Cohort Study

Background

Caffeine citrate (CC)-induced excessive energy expenditure, diuresis, natriuresis, and other CC-associated potential side effects (CC-APSEs) result in lower daily weight gain (WG) in premature neonates. This study aimed to assess higher CC-doses' effect on the mean daily-WG (MD-WG) and CC-APSE development, considering 5 mg/kg/day as the standard regimen.

Method

This retrospective cohort study included neonates of ≤36 weeks gestational age and received CC-therapy. The same participants were followed for data analysis in two postnatal phases: 15-28 and 29-42 days of life (DOL). Based on daily CC-dose, formed group-I=(5 mg/kg/day), group-II=(>5-7 mg/kg/day), and group-III=(>7 mg/kg/day). Data was analyzed separately for group-II and group-III using group-I as the standard.

Results

The study included 284 neonates. During phase-I, the MD-WG was significantly higher in group-I than group-II (19.9 ± .88 g/kg/d vs 17.5 ± .49, P = .031) and group-III (19.9 ± .88 g/kg/d vs 16.7 ± .71, P < .001). During 29-42 DOL, the MD-WG of group-I was only significantly higher than group-III (21.5 ± .42 g/kg/d vs 18.1 ± .39 g/kg/d, P = .003) and comparable with group-II. During 15-28 DOL, CC-APSEs were significantly higher in group-II and group-III but during 29-42 DOL was significant only in group-III.

Conclusion

Exposure to higher caffeine doses in this study cohort is associated with lower postnatal WG in preterm neonates than standard daily doses may be due to its catabolic effects and CC-APSEs.

Methylxanthine for the prevention and treatment of apnea in preterm infants

BACKGROUND

Very preterm infants often require respiratory support and are therefore exposed to an increased risk of chronic lung disease and later neurodevelopmental disability. Although methylxanthines are widely used to prevent and treat apnea associated with prematurity and to facilitate extubation, there is uncertainty about the benefits and harms of different types of methylxanthines.

OBJECTIVES

To assess the effects of methylxanthines on the incidence of apnea, death, neurodevelopmental disability, and other longer-term outcomes in preterm infants (1) at risk for or with apnea, or (2) undergoing extubation.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, two other databases, and three trial registers (November 2022).

SELECTION CRITERIA

We included randomized trials in preterm infants, in which methylxanthines (aminophylline, caffeine, or theophylline) were compared to placebo or no treatment for any indication (i.e. prevention of apnea, treatment of apnea, or prevention of re-intubation).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods and GRADE to assess the certainty of evidence.

MAIN RESULTS

We included 18 studies (2705 infants), evaluating the use of methylxanthine in preterm infants for: any indication (one study); prevention of apnea (six studies); treatment of apnea (five studies); and to prevent re-intubation (six studies). Death or major neurodevelopmental disability (DMND) at 18 to 24 months. Only the Caffeine for Apnea of Prematurity (CAP) study (enrolling 2006 infants) reported on this outcome. Overall, caffeine probably reduced the risk of DMND in preterm infants treated with caffeine for any indication (risk ratio (RR) 0.87, 95% confidence interval (CI) 0.78 to 0.97; risk difference (RD) -0.06, 95% CI -0.10 to -0.02; number needed to treat for an additional beneficial outcome (NNTB) 16, 95% CI 10 to 50; 1 study, 1869 infants; moderate-certainty evidence). No other trials reported DMND. Results from the CAP trial regarding DMND at 18 to 24 months are less precise when analyzed based on treatment indication. Caffeine probably results in little or no difference in DMND in infants treated for prevention of apnea (RR 1.00, 95% CI 0.80 to 1.24; RD -0.00, 95% CI -0.10 to 0.09; 1 study, 423 infants; moderate-certainty evidence) and probably results in a slight reduction in DMND in infants treated for apnea of prematurity (RR 0.85, 95% CI 0.71 to 1.01; RD -0.06, 95% CI -0.13 to 0.00; NNTB 16, 95% CI 7 to > 1000; 1 study, 767 infants; moderate-certainty evidence) or to prevent re-intubation (RR 0.85, 95% CI 0.73 to 0.99; RD -0.08, 95% CI -0.15 to -0.00; NNTB 12, 95% CI 6 to >1000; 1 study, 676 infants; moderate-certainty evidence). Death. In the overall analysis of any methylxanthine treatment for any indication, methylxanthine used for any indication probably results in little or no difference in death at hospital discharge (RR 0.99, 95% CI 0.71 to 1.37; I2 = 0%; RD -0.00, 95% CI -0.02 to 0.02; I2 = 5%; 7 studies, 2289 infants; moderate-certainty evidence). Major neurodevelopmental disability at 18 to 24 months. In the CAP trial, caffeine probably reduced the risk of major neurodevelopmental disability at 18 to 24 months (RR 0.85, 95% CI 0.76 to 0.96; RD -0.06, 95% CI -0.10 to -0.02; NNTB 16, 95% CI 10 to 50; 1 study, 1869 infants; moderate-certainty evidence), including a reduction in the risk of cerebral palsy or gross motor disability (RR 0.60, 95% CI 0.41 to 0.88; RD -0.03, 95% CI -0.05 to -0.01; NNTB 33, 95% CI 20 to 100; 1 study, 1810 infants; moderate-certainty evidence) and a marginal reduction in the risk of developmental delay (RR 0.88, 95% CI 0.78 to 1.00; RD -0.05, 95% CI -0.09 to -0.00; NNTB 20, 95% CI 11 to > 1000; 1 study, 1725 infants; moderate-certainty evidence). Any apneic episodes, failed apnea reduction after two to seven days (< 50% reduction in apnea) (for infants treated with apnea), and need for positive-pressure ventilation after institution of treatment. Methylxanthine used for any indication probably reduces the occurrence of any apneic episodes (RR 0.31, 95% CI 0.18 to 0.52; I2 = 47%; RD -0.38, 95% CI -0.51 to -0.25; I2 = 49%; NNTB 3, 95% CI 2 to 4; 4 studies, 167 infants; moderate-certainty evidence), failed apnea reduction after two to seven days (RR 0.48, 95% CI 0.33 to 0.70; I2 = 0%; RD -0.31, 95% CI -0.44 to -0.17; I2 = 53%; NNTB 3, 95% CI 2 to 6; 4 studies, 174 infants; moderate-certainty evidence), and may reduce receipt of positive-pressure ventilation after institution of treatment (RR 0.61, 95% CI 0.39 to 0.96; I2 = 0%; RD -0.06, 95% CI -0.11 to -0.01; I2 = 49%; NNTB 16, 95% CI 9 to 100; 9 studies, 373 infants; low-certainty evidence). Chronic lung disease. Methylxanthine used for any indication reduces chronic lung disease (defined as the use of supplemental oxygen at 36 weeks' postmenstrual age) (RR 0.77, 95% CI 0.69 to 0.85; I2 = 0%; RD -0.10, 95% CI -0.14 to -0.06; I2 = 18%; NNTB 10, 95% CI 7 to 16; 4 studies, 2142 infants; high-certainty evidence). Failure to extubate or the need for re-intubation within one week after initiation of therapy. Methylxanthine used for the prevention of re-intubation probably results in a large reduction in failed extubation compared with no treatment (RR 0.48, 95% CI 0.32 to 0.71; I2 = 0%; RD -0.27, 95% CI -0.39 to -0.15; I2 = 69%; NNTB 4, 95% CI 2 to 6; 6 studies, 197 infants; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

Caffeine probably reduces the risk of death, major neurodevelopmental disability at 18 to 24 months, and the composite outcome DMND at 18 to 24 months. Administration of any methylxanthine to preterm infants for any indication probably leads to a reduction in the risk of any apneic episodes, failed apnea reduction after two to seven days, cerebral palsy, developmental delay, and may reduce receipt of positive-pressure ventilation after institution of treatment. Methylxanthine used for any indication reduces chronic lung disease (defined as the use of supplemental oxygen at 36 weeks' postmenstrual age).

Caffeine versus other methylxanthines for the prevention and treatment of apnea in preterm infants

BACKGROUND

Methylxanthines, including caffeine, theophylline, and aminophylline, work as stimulants of the respiratory drive, and decrease apnea of prematurity, a developmental disorder common in preterm infants. In particular, caffeine has been reported to improve important clinical outcomes, including bronchopulmonary dysplasia (BPD) and neurodevelopmental disability. However, there is uncertainty regarding the efficacy of caffeine compared to other methylxanthines.

OBJECTIVES

To assess the effects of caffeine compared to aminophylline or theophylline in preterm infants at risk of apnea, with apnea, or in the peri-extubation phase.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Epistemonikos, the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP), and clinicaltrials.gov in February 2023. We also checked the reference lists of relevant articles to identify additional studies.

SELECTION CRITERIA

Studies: randomized controlled trials (RCTs) and quasi-RCTs Participants: infants born before 34 weeks of gestation for prevention and extubation trials, and infants born before 37 weeks of gestation for treatment trials Intervention and comparison: caffeine versus theophylline or caffeine versus aminophylline. We included all doses and duration of treatment.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We evaluated treatment effects using a fixed-effect model with risk ratio (RR), risk difference (RD), and 95% confidence intervals (CI) for categorical data, and mean, standard deviation, and mean difference for continuous data. We used the GRADE approach to evaluate the certainty of evidence.

MAIN RESULTS

We included 22 trials enrolling 1776 preterm infants. The indication for treatment was prevention of apnea in three studies, treatment of apnea in 13 studies, and extubation management in three studies. In three studies, there were multiple indications for treatment, and in one study, the indication for treatment was unclear. In 19 included studies, the infants had a mean gestational age between 28 and 32 weeks and a mean birth weight between 1000 g and 1500 g. One study's participants had a mean gestational age of more than 32 weeks, and two studies had participants with a mean birth weight of 1500 g or more. Caffeine administrated for any indication may result in little to no difference in all-cause mortality prior to hospital discharge compared to other methylxanthines (RR 1.12, 95% CI 0.68 to 1.84; RD 0.02, 95% CI -0.05 to 0.08; 2 studies, 396 infants; low-certainty evidence). Only one study enrolling 79 infants reported components of the outcome moderate to severe neurodevelopmental disability at 18 to 26 months. The evidence is very uncertain about the effect of caffeine on cognitive developmental delay compared to other methylxanthines (RR 0.17, 95% CI 0.02 to 1.37; RD -0.12, 95% CI -0.24 to 0.01; 1 study, 79 infants; very low-certainty evidence). The evidence is very uncertain about the effect of caffeine on language developmental delay compared to other methylxanthines (RR 0.76, 95% CI 0.37 to 1.58; RD -0.07, 95% CI -0.27 to 0.12; 1 study, 79 infants; very low-certainty evidence). The evidence is very uncertain about the effect of caffeine on motor developmental delay compared to other methylxanthines (RR 0.50, 95% CI 0.13 to 1.96; RD -0.07, 95% CI -0.21 to 0.07; 1 study, 79 infants; very low-certainty evidence). The evidence is very uncertain about the effect of caffeine on visual and hearing impairment compared to other methylxanthines. At 24 months of age, visual impairment was seen in 8 out of 11 infants and 10 out of 11 infants in the caffeine and other methylxanthines groups, respectively. Hearing impairment was seen in 2 out of 5 infants and 1 out of 1 infant in the caffeine and other methylxanthines groups, respectively. No studies reported the outcomes cerebral palsy, gross motor disability, and mental development. Compared to other methylxanthines, caffeine may result in little to no difference in BPD/chronic lung disease, defined as 28 days of oxygen exposure at 36 weeks' postmenstrual age (RR 1.40, 95% CI 0.92 to 2.11; RD 0.04, 95% CI -0.01 to 0.09; 3 studies, 481 infants; low-certainty evidence). The evidence is very uncertain about the effect of caffeine on side effects (tachycardia, agitation, or feed intolerance) leading to a reduction in dose or withholding of methylxanthines compared to other methylxanthines (RR 0.17, 95% CI 0.02 to 1.32; RD -0.29, 95% CI -0.57 to -0.02; 1 study, 30 infants; very low-certainty evidence). Caffeine may result in little to no difference in duration of hospital stay compared to other methylxanthines (median (interquartile range): caffeine 43 days (27.5 to 61.5); other methylxanthines 39 days (28 to 55)). No studies reported the outcome seizures.

AUTHORS' CONCLUSIONS

Although caffeine has been shown to improve important clinical outcomes, in the few studies that compared caffeine to other methylxanthines, there might be little to no difference in mortality, bronchopulmonary dysplasia, and duration of hospital stay. The evidence is very uncertain about the effect of caffeine compared to other methylxanthines on long-term development and side effects. Although caffeine or other methylxanthines are widely used in preterm infants, there is little direct evidence to support the choice of which methylxanthine to use. More research is needed, especially on extremely preterm infants born before 28 weeks of gestation. Data from four ongoing studies might provide more evidence on the effects of caffeine or other methylxanthines.

Caffeine versus other methylxanthines for the prevention and treatment of apnea in preterm infants

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To assess the effects of caffeine compared to aminophylline or theophylline in preterm infants at risk of apnea, with apnea, or in the peri‐extubation phase.

Effects of early aminophylline therapy on clinical outcomes in premature infants

BACKGROUND

Aminophylline use and the association between clinical outcomes and therapy timing have been less investigated. The objective of this study was to determine the efficacy of early aminophylline use (within the first two days of life) in premature infants.

METHOD

A retrospective observational cohort of infants weighing <1500 g and <30 weeks of gestational age at Kaohsiung Veterans General Hospital received aminophylline either within the first two days of life (EA, early aminophylline group), after the third day of life (LA, late aminophylline group), or without aminophylline during the first month of life (WA, without aminophylline group). Demographic data and neonatal clinical outcomes were compared among the three groups.

RESULTS

This study included 89 preterm infants (EA = 33, LA = 38, WA = 18). The EA group had a lower incidence of bronchopulmonary dysplasia (BPD) than the WA group (adjusted odds ratio [aOR] = 8.86(1.56-59.32); P = 0.024). Although there was no significant difference in BPD incidence between the EA and LA groups (aOR = 2.66(0.51-13.81), P = 0.244), a trend remained. Birth body weight less than 1000 g was also a significant risk factor for BPD (aOR = 8.86(1.32-47.41), P = 0.014). The duration of mechanical ventilation was shorter in the infants in the EA group compared to the WA group (estimated beta = -11.344(-19.57-3.12); P = 0.008).

CONCLUSION

Early aminophylline administration may be associated with a decreased incidence of BPD in preterm infants. However, the clinical benefits of aminophylline treatment require further investigation. In addition, a birth body weight of less than 1000 g was a crucial risk factor for BPD.

Comparative efficacy and safety of caffeine citrate and aminophylline in treating apnea of prematurity: A systematic review and meta-analysis

Background

Methylxanthine, including caffeine citrate and aminophylline, is the most common pharmacologic treatment for apnea of prematurity. However, due to the lack of high-quality evidence, there are no clear recommendations or guidelines on how to choose between caffeine and aminophylline.

Objective

This meta-analysis aimed to assess the comparative efficacy and safety of caffeine and aminophylline for apnea of prematurity, and provide reliable evidence for clinical medication in the treatment for apnea of prematurity.

Methods

PubMed, Scopus, Embase, EBSCO, Web of Science, and Cochrane databases were systematically searched from May 1975 to June 2022.

Results

Ten studies including a total of 923 preterm infants were evaluated. Our results showed that there was no significant difference in the effective rate of 1-3days between caffeine and aminophylline (OR 1.05, 95%CI: 0.40–2.74, P = 0.914). However, for side effects such as tachycardia (OR 0.22, 95%CI: 0.13–0.37, P<0.001) and feeding intolerance (OR 0.40, 95%CI: 0.23–0.70, P = 0.001), the incidence rate was lower in the caffeine group compared with the aminophylline group. No significant difference was found in hyperglycemia (OR 0.45, 95%CI: 0.19–1.05, P = 0.064).

Conclusion

This meta-analysis reveals that caffeine citrate and aminophylline have similar therapeutic effectiveness on respiratory function, but caffeine has fewer side effects and should be considered first for treatment.

Specific Premature Groups Have Better Benefits When Treating Apnea With Caffeine Than Aminophylline/Theophylline

Background

Methylxanthines (caffeine; aminophylline/theophylline) are commonly used for apnea of prematurity (AOP) treatment. We aimed to compare the efficacy and adverse effects of caffeine and aminophylline/theophylline.

Methods

A retrospective case-control gestational age-matched study investigates patients born between January 2017 and December 2018, 23-35 weeks gestation with birth weights >500 g treating AOP with caffeine or aminophylline/theophylline.

Results

There were 144 cases (48 in caffeine group and 96 in aminophylline/theophylline group). The median treatment durations were 11 and 17 days in caffeine and aminophylline/theophyllinegroup (p = 0.002). When tachycardia is defined as heart rate ≥160 bpm, the rates were 8.3 and 34.4% in caffeine and control group (p = 0.001). When tachycardia is defined as 10 bpm over baseline heart rate, the rates were 41.7 and 63.5% in caffeine and aminophylline/theophylline group (p = 0.01). Stratified by gestational age and sex, significant reductions in tachycardia rates with caffeine than with theophylline were limited to male infants and infants born at <30 weeks gestation.

Conclusions

For apnea treatment, caffeine has greater efficacy and fewer tachycardia than aminophylline/theophylline, especially in male infants and infants born at <30 weeks gestation.

Caffeine versus aminophylline in combination with oxygen therapy for apnea of prematurity: A retrospective cohort study

The present study was conducted to investigate the clinical significance of caffeine and aminophylline in the treatment of premature infants with apnea under varying conditions of oxygen (O2) delivery. The clinical data of 120 premature infants with apnea treated with oxygen therapy and either caffeine citrate (20 mg/kg/day; n=77) or aminophylline (10 mg/kg/day; n=43) were retrospectively examined. The therapeutic performance of the drugs after the completion of the treatment was evaluated primarily according to the risk of recurrent episodes of apnea, the changes in the duration and concentration of inhaled O2 and the incidence of complications. In contrast to aminophylline, caffeine treatment significantly reduced the duration of O2 inhalation and the inhaled O2 concentration in the infants treated with mechanical ventilation or O2 delivery devices (P<0.05). Treatment with caffeine also decreased the incidence of recurrent apnea events and complications in the investigated population (P<0.05 or P<0.01). Caffeine performs better than aminophylline in the treatment of premature infants with apnea under different conditions of O2 delivery. The therapeutic performance of caffeine is achieved primarily via improving the efficacy of supplemental O2 and reducing the incidence of complications.

Developmental population pharmacokinetics of caffeine in Chinese premature infants with apnoea of prematurity: A post-marketing study to support paediatric labelling in China

AIMS

The aim of the study was to evaluate the suitability of the current caffeine dosing regimen for the Chinese population using modelling and simulation approach.

METHODS

Pharmacokinetic samples were collected from 99 Chinese newborns with premature apnoea. The median (range) of gestational age and postmenstrual age were 28.3 (25.0-33.4) weeks and 31.1 (26.4-38.0) weeks, respectively. Newborns were receiving caffeine citrate at a loading dose of 20 mg/kg/d and a maintenance dose of 5-10 mg/kg/d. Caffeine concentrations and CYP1A2 polymorphisms were investigated. Population pharmacokinetic modelling of caffeine in Chinese preterm newborn on a population-wide scale was conducted using NONMEM.

RESULTS

A 1-compartment model with first-order elimination was used to describe population pharmacokinetic. With current weight implemented using 0.75 allometric scaling, clearance (CL) was positively related to current weight and postmenstrual age, but a negative relationship was observed with serum creatinine concentration. Eight genotypes of CYP1A2 were tested and none of them had a significant impact on caffeine pharmacokinetic parameters. Interindividual variability of CL and volume of distribution was 7.70 and 65.9%. The median (range) of 95% confidence intervals of CL were 0.0128 (0.0128-0.0131) L/h/kg. Monte Carlo simulation demonstrated that 80% (loading dose) and 98% (maintenance dose) of premature infants treated with a labelled dosing regimen attained the concentration target range of 5-20 mg/L.

CONCLUSION

A population PK model of caffeine was developed in Chinese newborns. Body weight-implemented allometric scaling, postmenstrual age and serum creatinine concentration markedly affected caffeine clearance. The labelled dosing regimen is suitable for Chinese premature infants.

Stopping caffeine in premature neonates: how long does it take for the level of caffeine to fall below the therapeutic range?

Background: Caffeine is routinely used in preterm infants for apnea of prematurity. Preterm infants are usually monitored for 5 days after discontinuation of caffeine to assess for possible recurrence of apnea. Our objective was to determine if the serum concentration of caffeine decreases to a subtherapeutic level 5 days after its discontinuation.Methods: This is a retrospective analysis of caffeine levels after the drug was discontinued in preterm neonates (birth weight ≤1500 g) born between January 2010 and June 2017. The primary outcome was the proportion of infants with therapeutic levels of caffeine 5 days after the drug was stopped.Results: Caffeine levels were measured in 353 samples from 280 infants (birth weight 1246 ± 390 g and gestational age 29.2 ± 2.4 weeks) after discontinuation of the drug. Five and more days after discontinuation of caffeine, 29.3% (82/280) of the infants had caffeine levels ≥5 mg/L. Approximately 41% (75/181) of the caffeine levels measured between 5 and 7 days and 18% (17/95) between 8 and 10 days were ≥5 mg/L. A caffeine dose of >5 mg/kg/day when discontinued was associated with the caffeine level of ≥5 mg/L (OR 2.3, 95% CI 1.28-4.13, p = .005).Conclusions: Preterm infants treated with caffeine frequently had therapeutic levels of caffeine 5-10 days after discontinuation of the drug. The infants receiving higher doses were more likely to have a therapeutic level of caffeine 5 days after stopping the medication. Preterm infants should be monitored for recurrence of apnea for more than 5 days after stopping caffeine or levels should be monitored prior to discharge.

Caffeine not associated with irritable behaviour in very low-birth-weight infants

This paper is an examination of irritable behaviour in very low-birth-weight infants in relation to caffeine or aminophylline. We assessed tremulous movement (a sub-score of General Movements Optimality Score) in 18 caffeine-treated subjects and 18 aminophylline-treated subjects. Caffeine, unlike aminophylline, was not associated with irritable behaviour at standard dose.

[Clinical effect and safety of different maintenance doses of caffeine citrate in treatment of apnea in very low birth weight preterm infants: a prospective randomized controlled trial]

OBJECTIVE

To study the clinical effect and safety of different maintenance doses of caffeine citrate in the treatment of apnea in very low birth weight preterm infants.

METHODS

A total of 78 very low birth weight preterm infants with primary apnea were enrolled who were admitted from January 2016 to January 2018. They were randomly divided into high-dose caffeine group with 38 children and low-dose caffeine group with 40 children. Both groups received a loading dose of 20 mg/kg caffeine citrate, and 24 hours later, the children in the high-dose caffeine group were given a maintenance dose of 10 mg/kg, and those in the low-dose caffeine group were given a maintenance dose of 5 mg/kg. The two groups were compared in terms of response rate and incidence rate of adverse events.

RESULTS

The high-dose caffeine group had a significantly higher response rate than the low-dose caffeine group (71% vs 48%; P<0.05). Compared with the low-dose caffeine group, the high-dose caffeine group had significantly shorter duration of apnea and time of caffeine treatment (P<0.05). There were no significant differences between the two groups in length of hospital stay and incidence rates of tachycardia, feeding intolerance, bronchopulmonary dysplasia, necrotizing enterocolitis, and intracranial hemorrhage (P>0.05). There was no significant difference in the mortality rate between the two groups (P>0.05).

CONCLUSIONS

Higher maintenance dose of caffeine citrate has a better clinical effect than lower maintenance dose of caffeine citrate in the treatment of apnea in very low birth weight preterm infants, without increasing the incidence rates of adverse drug reactions and serious complications in preterm infants.

[Clinical effect and safety of different maintenance doses of caffeine citrate in treatment of apnea in very low birth weight preterm infants: a prospective randomized controlled trial]

OBJECTIVE

To study the clinical effect and safety of different maintenance doses of caffeine citrate in the treatment of apnea in very low birth weight preterm infants.

METHODS

A total of 78 very low birth weight preterm infants with primary apnea were enrolled who were admitted from January 2016 to January 2018. They were randomly divided into high-dose caffeine group with 38 children and low-dose caffeine group with 40 children. Both groups received a loading dose of 20 mg/kg caffeine citrate, and 24 hours later, the children in the high-dose caffeine group were given a maintenance dose of 10 mg/kg, and those in the low-dose caffeine group were given a maintenance dose of 5 mg/kg. The two groups were compared in terms of response rate and incidence rate of adverse events.

RESULTS

The high-dose caffeine group had a significantly higher response rate than the low-dose caffeine group (71% vs 48%; P<0.05). Compared with the low-dose caffeine group, the high-dose caffeine group had significantly shorter duration of apnea and time of caffeine treatment (P<0.05). There were no significant differences between the two groups in length of hospital stay and incidence rates of tachycardia, feeding intolerance, bronchopulmonary dysplasia, necrotizing enterocolitis, and intracranial hemorrhage (P>0.05). There was no significant difference in the mortality rate between the two groups (P>0.05).

CONCLUSIONS

Higher maintenance dose of caffeine citrate has a better clinical effect than lower maintenance dose of caffeine citrate in the treatment of apnea in very low birth weight preterm infants, without increasing the incidence rates of adverse drug reactions and serious complications in preterm infants.

Comparison of Caffeine versus Theophylline for apnea of prematurity

Objective:

To make a comparison between standard doses of theophylline and caffeine for the treatment of apnea of prematurity.

Methods:

A randomised control trail was conducted in Department of Pediatrics Medicine Govt. Khawaja Muhammad Safdar Medical College and Govt. Allama Iqbal Memorial Teaching Hospital, Sialkot over duration of one year from August 2017 to August 2018 after approval from the hospital ethics committee. An informed consent in the form of written document was also taken from the parents of each infant participating in the study. Data was analyzed by using SPSS version 24. Mean and SD was calculated for numerical data like gestational age and mean concentration of caffeine and theophylline. Frequency and percentages were calculated for categorical data like nasal continuous positive airway pressure (CPAP), supplemental oxyen and intrventricular hemorrhage (IVH) grade I. Student t-test was applied in order to determine the significance of results. P value ≤ 0.05 was considered significant.

Results:

A total of 100 infants were enrolled in this study. This study was further divided into two equal groups by lottery method i.e. 50% in each, treated with Theophylline and Caffeine respectively. Mean apnea events/day in neonates administrated by theophylline was 1±0.1, 2±0.12, 2±1.1, 1±0.10 and 2±o.12 for 0, 1-3, 4-7, 8-14 and 15-21 days respectively. While, the mean apnea events/day in neonates administrated by Caffeine was 2±0.3, 1±0.22, 2±1.5, 1±0.13 and 2±0.14 for 0, 1-3, 4-7, 8-14 and 15-21 days respectively. The differences were statistically significant for 1-3 days and 4-7 days p<0.05 according to student t test.

Conclusion:

Results of our study revealed that caffeine being more effective than Theophylline for treating apnea of prematurity.

Factors affecting the efficacy and safety of aminophylline in treatment of apnea of prematurity in neonatal intensive care unit

BACKGROUND

The factors affecting the safety and efficacy of aminophylline use in the treatment of apnea of prematurity (AOP) in the neonatal intensive care unit (NICU) are not clear. In this study, we aimed to evaluate the potential factors affecting the efficacy and safety of aminophylline in AOP treatment at standard doses and to determine appropriate patients for this therapy.

METHODS

Over a 3-year period (January 2012 to December 2014), the medical records of 206 preterm infants with apnea who were admitted to the NICU of our hospital to receive aminophylline infusions were retrospectively reviewed. These infants were subjected to routine theophylline monitoring by reversed-phase high performance liquid chromatography. The primary outcome measures were the efficacy of aminophylline treatment and adverse reactions observed upon administration.

RESULTS

One-hundred and twenty-seven (61.65%) infants were considered to have undergone effective therapy and classified accordingly. Gestational age, body weight at the initiation of aminophylline, and serum theophylline concentration were identified as protective factors of therapeutic efficacy. Receiver operating characteristic (ROC) analysis indicated cutoff values of 30.36 weeks for gestational age and 1.69 kg for body weight at initiation of aminophylline administration for ensuring high efficacy of aminophylline for AOP. Fifty-three (25.73%) infants had adverse reactions. Birth weight and serum concentration of theophylline were associated with an increased risk of adverse reactions, with odds ratios of 0.167 and 1.346, respectively. The ROC curves indicated a birth weight cutoff value of 1.48 kg.

CONCLUSION

Infants with apnea and gestational age >30.36 weeks, body weight at initiation of aminophylline treatment above 1.69 kg, and birth weight >1.48 kg are suitable for treatment with aminophylline. Monitoring of serum theophylline concentration should be implemented in the absence of clinical response or in case of suspected adverse reactions.

Diprophylline inhibits non-small cell lung cancer A549 cell proliferation and migration, and promotes apoptosis, by downregulating PI3K signaling pathway

Diprophylline (DPL) is identified as a methylxanthine (MX) derivative. A number of MX derivatives are reported to have anti-tumor effects. However, it is not clear whether DPL has a therapeutic effect on non-small cell lung cancer (NSCLC). The aim of the present study was to investigate the effects of DPL on NSCLC and to elucidate the potential underlying mechanism. A Cell Counting Kit-8 assay was used to evaluate the potential effect of DPL on A549 cell proliferation. Transwell invasion and migration assays were performed to assess the effect of DPL on A549 cell migration and invasion. Furthermore, the percentage of apoptotic cells was detected by flow cytometric analysis, and proteins associated with apoptosis, including apoptosis regulator Bcl-2, apoptosis regulator BAX and active caspase-3, were examined by western blotting. Finally, the expression levels of molecules relevant to phosphoinositide 3-kinase (PI3K) signaling were detected by western blot analysis. The present study demonstrated that DPL may significantly inhibit A549 cell proliferation, migration and invasion. Furthermore, treatment with DPL may significantly induce A549 cell apoptosis. Finally, the protein expression levels associated with the PI3K signaling pathway were significantly inhibited in A549 cells following treatment with DPL. In conclusion, DPL may inhibit the proliferation and migration of NSCLC by inactivating the PI3K signaling pathway, and DPL is a promising novel therapeutic drug for NSCLC.

Phosphodiesterase inhibitors: Potential role in the respiratory distress of neonates

Phosphodiesterases (PDEs) are a superfamily of enzymes that catalyze the hydrolysis of phosphodiester bonds of 3',5' cyclic adenosine and guanosine monophosphate (cAMP and cGMP). PDEs control hydrolysis of cyclic nucleotides in many cells and tissues. Inhibition of PDEs by selective or nonselective PDE inhibitors represents an effective targeted strategy for the treatment of various diseases including respiratory disorders. Recent data have demonstrated that PDE inhibitors can also be of benefit in respiratory distress in neonates. This article outlines the pharmacological properties of nonselective and selective PDE inhibitors and provides up-to-date information regarding their use in experimental models of neonatal respiratory distress as well as in clinical studies.

Long-term neurodevelopment outcome of caffeine versus aminophylline therapy for apnea of prematurity

OBJECTIVE

Methylxanthines are the most commonly prescribed drug in neonatal setups. However, Clinicians show indecision in choosing the right agent for Apnea of Prematurity in most of the developing countries. Present study aimed to compare rate of mortality and survival with normal neurodevelopment outcome at 18 to 24 months of corrected age, between Caffeine- and Aminophylline-treated infants for apnea of prematurity.

METHODS

240 infants were randomly allocated to caffeine and aminophylline for apnea of prematurity during February 2012 to January 2015. Long-term neurodevelopmental assessment was done only from children who had attained corrected age of 18 to 24 months during April 2014 to February 2016. Cognitive, language and motor deficits were assessed by Bayley Scale of infant and toddler development (BSID - III). Postnatal characteristics such as hearing and visual impairments during NICU stay were noted and same were followed up.

RESULTS

Infants allocated to caffeine group showed 83% less risk of getting cognitive impairment (RR 0.16; CI 95% range 0.02 to 1.36), 50% less risk of developing motor deficits (RR 0.50; CI 95% range 0.12 to 1.95) and 24% less risk of developing language problems (RR 0.76; CI 95% range 0.36 to 1.58). However in all the neurodevelopment domains the difference between groups was not statistically significant. Risk of mortality in caffeine group was 9% less over aminophylline group which was statistically non-significant (RR - 0.92; CI 95% range - 0.45 to 1.84; p = 0.81). Physical growth parameters were found to be similar in both the groups. Risk of developing visual abnormality and hearing impairments was also statistically non-significant between the groups.

CONCLUSION

Caffeine and aminophylline showed similar effects in reducing the rate of mortality and improving the survival without neurodevelopment delays; though the clinical significance of caffeine over aminophylline cannot be undermined.

Adenosine A2A receptor antagonists act at the hyperoxic phase to confer protection against retinopathy

BACKGROUND

Retinopathy of prematurity (ROP) remains a major cause of childhood blindness and current laser photocoagulation and anti-VEGF antibody treatments are associated with reduced peripheral vision and possible delayed development of retinal vasculatures and neurons. In this study, we advanced the translational potential of adenosine A_2A receptor (A_2AR) antagonists as a novel therapeutic strategy for selectively controlling pathological retinal neovascularization in oxygen-induced retinopathy (OIR) model of ROP.

METHODS

Developing C57BL/6 mice were exposed to 75% oxygen from postnatal (P) day 7 to P12 and to room air from P12 to P17 and treated with KW6002 or vehicle at different postnatal developmental stages. Retinal vascularization was examined by whole-mount fluorescence and cross-sectional hematoxylin-eosin staining. Cellular proliferation, astrocyte and microglial activation, and tip cell function were investigated by isolectin staining and immunohistochemistry. Apoptosis was analyzed by TUNEL assay. The effects of oxygen exposure and KW6002 treatment were analyzed by two-way ANOVA or Kruskal-Wallis test or independent Student's t-test or Mann-Whitney U test.

RESULTS

The A_2AR antagonist KW6002 (P7-P17) did not affect normal postnatal development of retinal vasculature, but selectively reduced avascular areas and neovascularization, with the reduced cellular apoptosis and proliferation, and enhanced astrocyte and tip cell functions in OIR. Importantly, contrary to our prediction that A_2AR antagonists were most effective at the hypoxic phase with aberrantly increased adenosine-A_2AR signaling, we discovered that the A_2AR antagonist KW6002 mainly acted at the hyperoxic phase to confer protection against OIR as KW6002 treatment at P7-P12 (but not P12-P17) conferred protection against OIR; this protection was observed as early as P9 with reduced avascular areas and reduced cellular apoptosis and reversal of eNOS mRNA down-regulation in retina of OIR.

CONCLUSIONS

As ROP being a biphasic disease, our identification of the hyperoxic phase as the effective window, together with selective and robust protection against pathological (but not physiological) angiogenesis, elevates A_2AR antagonists as a novel therapeutic strategy for ROP treatment.

Pharmacological potential of methylxanthines: Retrospective analysis and future expectations

Methylated xanthines (methylxanthines) are available from a significant number of different botanical species. They are ordinarily included in daily diet, in many extremely common beverages and foods. Caffeine, theophylline and theobromine are the main methylxanthines available from natural sources. The supposedly relatively low toxicity of methylxanthines, combined with the many beneficial effects that have been attributed to these compounds through time, generated a justified attention and a very prolific ground for dedicated scientific reports. Methylxanthines have been widely used as therapeutical tools, in an intriguing range of medicinal scopes. In fact, methylxanthines have been/were medically used as Central Nervous System stimulants, bronchodilators, coronary dilators, diuretics and anti-cancer adjuvant treatments. Other than these applications, methylxanthines have also been hinted to hold other beneficial health effects, namely regarding neurodegenerative diseases, cardioprotection, diabetes and fertility. However, it seems now consensual that toxicity concerns related to methylxanthine consumption and/or therapeutic use should not be dismissed. Taking all the knowledge and expectations on the potential of methylxanthines into account, we propose a systematic look at the past and future of methylxanthine pharmacologic applications, discussing all the promise and anticipating possible constraints. Anyways, methylxanthines will still substantiate considerable meaningful research and discussion for years to come.

[Comparative Study of the Efficacy and Safety of Caffeine and Aminophylline for the Treatment of Apnea in Preterm Infants]

　Methylxanthine is widely administered for the treatment of apnea of prematurity in many countries, and previous reports have clearly established that caffeine is effective for the treatment of apnea of prematurity. In Japan, caffeine has been available since December 2014. Thus, we compared the efficacy and safety of caffeine with that of aminophylline in our hospital. There was no significant difference between the caffeine group and aminophylline group regarding the characteristics of the study patients. The mean efficacy rate from day 1 to day 10 was 89.5% in the caffeine group, and 81.9% in the aminophylline group, although the rate of improvement in apnea episodes each day from day 1 to day 10 was not significantly different between the two groups. On the other hand, the adverse event rates in the caffeine group and the aminophylline group were 70.6% and 75.0%, respectively. No significant difference was observed in the adverse event rates between the two groups. Moreover, suspected abdominal distension due to the drug administration was more frequently observed with the aminophylline group. Our findings indicate that caffeine is as effective as aminophylline, while it is superior to aminophylline regarding its overall safety.

Retrospective study shows that doxapram therapy avoided the need for endotracheal intubation in most premature neonates

AIM

Using doxapram to treat neonates with apnoea of prematurity might avoid the need for endotracheal intubation and invasive ventilation. We studied whether doxapram prevented the need for intubation and identified the predictors of the success.

METHODS

This was a retrospective study of preterm infants born from January 2006 to August 2014 who received oral or intravenous doxapram. Success was defined as no need for endotracheal intubation, due to apnoea, during doxapram therapy. Univariable and multivariable logistic regression analyses identified predictors of success during the first 48 hours of doxapram therapy.

RESULTS

Data on 203 patients with a median gestational age of 26.1 (interquartile range 25.1-27.4) weeks were analysed. During the first 48 hours of doxapram therapy, 157 (77%) patients did not need endotracheal intubation and 127 (63%) patients were successfully treated over the entire treatment course. The median postnatal age at the start of doxapram therapy was 20 days (interquartile range 12-30). Postnatal age and a lower fraction of inspired oxygen at the start of doxapram therapy were significant predictors of success (odds ratio 0.964, 95% confidence interval 0.938-0.991, p = 0.001).

CONCLUSION

Oral and intravenous doxapram effectively treated most cases of apnoea in preterm infants, avoiding the need for intubation.

Caffeine preferentially protects against oxygen-induced retinopathy

Retinopathy of prematurity (ROP) is the leading cause of childhood blindness, but current anti-VEGF therapy is concerned with delayed retinal vasculature, eye, and brain development of preterm infants. The clinical observation of reduced ROP severity in premature infants after caffeine treatment for apnea suggests that caffeine may protect against ROP. Here, we demonstrate that caffeine did not interfere with normal retinal vascularization development but selectively protected against oxygen-induced retinopathy (OIR) in mice. Moreover, caffeine attenuated not only hypoxia-induced pathologic angiogenesis, but also hyperoxia-induced vaso-obliteration, which suggests a novel protection window by caffeine. At the hyperoxic phase, caffeine reduced oxygen-induced neural apoptosis by adenosine A_2A receptor (A_2AR)-dependent mechanism, as revealed by combined caffeine and A_2AR-knockout treatment. At the hypoxic phase, caffeine reduced microglial activation and enhanced tip cell formation by A_2AR-dependent and -independent mechanisms, as combined caffeine and A_2AR knockout produced additive and nearly full protection against OIR. Together with clinical use of caffeine in neonates, our demonstration of the selective protection against OIR, effective therapeutic window, adenosine receptor mechanisms, and neuroglial involvement provide the direct evidence of the novel effects of caffeine therapy in the prevention and treatment of ROP.-Zhang, S., Zhou, R., Li, B., Li, H., Wang, Y., Gu, X., Tang, L., Wang, C., Zhong, D., Ge, Y., Huo, Y., Lin, J., Liu, X.-L., Chen, J.-F. Caffeine preferentially protects against oxygen-induced retinopathy.

Health benefits of methylxanthines in neurodegenerative diseases

Methylxanthines (MTXs) are consumed by almost everybody in almost every area of the world. Caffeine, theophylline and theobromine are the most well-known members of this family of compounds; they are present, inter alia, in coffee, tea, cacao, yerba mate and cola drinks. MTXs are readily absorbed in the gastrointestinal tract and are able to penetrate into the central nervous system, where they exert significant psychostimulant actions, which are more evident in acute intake. Coffee has been paradigmatic, as its use was forbidden in many diseases, however, this negative view has radically changed; evidence shows that MTXs display health benefits in diseases involving cell death in the nervous system. This paper reviews data that appraise the preventive and even therapeutic potential of MTXs in a variety of neurodegenerative diseases. Future perspectives include the use of MTXs to advance the understanding the pathophysiology of, inter alia, Alzheimer's disease (AD) and Parkinson's disease (PD), and the use of the methylxanthine chemical moiety as a basis for the development of new and more efficacious drugs.

Spontaneous symmetry breaking on ordered, racemic monolayers of achiral theophylline: formation of unichiral stripes on Au(111)

We report the observation of spontaneous chiral symmetry breaking within ordered, racemic monolayers of theophylline, manifesting itself as extended, nanoscale unichiral stripes at the interface between molecular domains. Theophylline is a xanthine derivative playing an important role in several biochemical processes. Molecular chirality is induced by adsorption on the Au(111) surface, resulting in extended domains with two different racemic, ordered structures, coexisting with a disordered phase. By combining low-temperature scanning tunneling microscopy (LT-STM) and ab initio density functional theory calculations, we first provide a detailed picture of the interactions within the ordered assemblies, and we uncover the origin of the distinct contrast features in STM images. Secondly, experiments reveal the existence of nanoscale stripes of unichiral molecules separating racemic domains of one of the two ordered phases, giving rise to a local enantiomeric imbalance. Systematic theoretical investigation of their structure and chiral composition confirm their unichirality, with the specific handedness related to the registry between the two ordered domains facing the stripes. These findings can open the way to new insights into the elusive mechanisms leading to local chiral imbalances in racemic systems, possibly at the origin of biomolecular homochirality, as well as suggest novel approaches for stereoselective heterogeneous catalysis.

Caffeine for the Treatment of Apnea in Bronchiolitis: A Randomized Trial

OBJECTIVE

To evaluate the efficacy and safety of caffeine citrate in the treatment of apnea in bronchiolitis.

STUDY DESIGN

Eligible infants aged ≤4 months presenting to the main pediatric emergency service with apnea associated bronchiolitis were stratified by gestational age (<34 weeks or longer) and randomized to receive a single dose of intravenous 25 mg/kg caffeine citrate or saline placebo. The primary efficacy outcome was a 24-hour apnea-free period beginning after completion of the blinded study drug infusion. Secondary outcomes were frequency of apnea by 24, 48, and 72 hours after study medication, need for noninvasive/invasive ventilation, and length of stay in the hospital's pediatric intensive care/step-down unit.

RESULTS

A total of 90 infants diagnosed with viral bronchiolitis associated with apnea (median age, 38 days) were enrolled. The rate of respiratory virus panel positivity was similar in the 2 groups (78% for the placebo group vs 84% for the caffeine group). The geometric mean duration to a 24-hour apnea-free period was 28.1 hours (95% CI, 25.6-32.3 hours) for the caffeine group and 29.1 hours (95% CI, 25.7-32.9 hours) for the placebo group (P = .88; OR, 0.99; 95% CI, 0.83-1.17). The frequency of apnea at 24 hours, 24-48 hours, and 48-72 hours after enrollment and the need for noninvasive and invasive ventilation were similar in the 2 groups. No safety issues were reported.

CONCLUSIONS

A single dose of caffeine citrate did not significantly reduce apnea episodes associated with bronchiolitis.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT01435486.

[Current research status of drug therapy for apnea of prematurity]

OBJECTIVE

To investigate the current status of studies on drug therapy for apnea of prematurity (AOP) in the past decade in China and abroad, and to describe the research trends in the field.

METHODS

CNKI and MEDLINE were searched with the key words "apnea of prematurity" and "treatment" for articles published in the past decade (January 2006 to December 2015). The articles were screened and the key words were extracted to establish the co-occurrence matrix. Ucinet 6.2 was used to plot the knowledge map.

RESULTS

A total of 26 Chinese key words and 20 English key words were included. Those in the center of the co-existent knowledge map of Chinses keywords were "preterm infants", "apnea", "primary apnea", "naloxone" and "aminophylline"; while "apnea", "preterm infants" and "caffeine" located in the central place of the co-existent knowledge map of English keywords.

CONCLUSIONS

Methylxanthines are still the major drugs for AOP; however, aminophylline is mainly used in China, while caffeine is mainly used in foreign countries. Other drugs such as naltrexone are also used in the clinical treatment of AOP.

[Current research status of drug therapy for apnea of prematurity]

OBJECTIVE

To investigate the current status of studies on drug therapy for apnea of prematurity (AOP) in the past decade in China and abroad, and to describe the research trends in the field.

METHODS

CNKI and MEDLINE were searched with the key words "apnea of prematurity" and "treatment" for articles published in the past decade (January 2006 to December 2015). The articles were screened and the key words were extracted to establish the co-occurrence matrix. Ucinet 6.2 was used to plot the knowledge map.

RESULTS

A total of 26 Chinese key words and 20 English key words were included. Those in the center of the co-existent knowledge map of Chinses keywords were "preterm infants", "apnea", "primary apnea", "naloxone" and "aminophylline"; while "apnea", "preterm infants" and "caffeine" located in the central place of the co-existent knowledge map of English keywords.

CONCLUSIONS

Methylxanthines are still the major drugs for AOP; however, aminophylline is mainly used in China, while caffeine is mainly used in foreign countries. Other drugs such as naltrexone are also used in the clinical treatment of AOP.

Structure-Bioactivity Relationships of Methylxanthines: Trying to Make Sense of All the Promises and the Drawbacks

Methylxanthines are a group of phytochemicals derived from the purine base xanthine and obtained from plant secondary metabolism. They are unobtrusively included in daily diet in common products as coffee, tea, energetic drinks, or chocolate. Caffeine is by far the most studied methylxanthine either in animal or epidemiologic studies. Theophylline and theobromine are other relevant methylxanthines also commonly available in the aforementioned sources. There are many disseminated myths about methylxanthines but there is increased scientific knowledge to discuss all the controversy and promise shown by these intriguing phytochemicals. In fact, many beneficial physiologic outcomes have been suggested for methylxanthines in areas as important and diverse as neurodegenerative and respiratory diseases, diabetes or cancer. However, there have always been toxicity concerns with methylxanthine (over)consumption and pharmacologic applications. Herein, we explore the structure-bioactivity relationships to bring light those enumerated effects. The potential shown by methylxanthines in such a wide range of conditions should substantiate many other scientific endeavors that may highlight their adequacy as adjuvant therapy agents and may contribute to the advent of functional foods. Newly designed targeted molecules based on methylxanthine structure may originate more specific and effective outcomes.

Treatment options for apnoea of prematurity

Apnoea of prematurity (AOP) affects almost all infants born at <28 weeks gestation or with birth weight <1000 g. When untreated, AOP may be associated with negative outcomes. Because of these negative outcomes, effective treatment for AOP is an important part of optimising care of preterm infants. Standard treatment usually involves xanthine therapy and respiratory support. Cutting-edge work with stochastic vibrotactile stimulation and new pharmaceutical agents continues to expand therapeutic options. In this article, we review the pathophysiology of AOP, associated conditions and treatment options.

Incorporating pharmacodynamic considerations into caffeine therapeutic drug monitoring in preterm neonates

Background

This study sought to assess the pharmacokinetic and pharmacodynamic relationships of caffeine citrate therapy in preterm neonates who had therapeutic drug monitoring (TDM) in the post-extubation period.

Methods

A retrospective observational study was conducted in preterm neonates who received caffeine citrate therapy for apnea of prematurity and had TDM done in the post-extubation period between January 2006 and October 2011. The relationships between pharmacodynamic effects (heart rate, respiratory rate, episodes of apnea, adverse events) and caffeine serum concentrations were explored.

Results

A total of 177 blood samples were obtained from 115 preterm neonates with a median (range) gestational age of 29 (24 – 33) weeks and birth weight of 1230 (607 – 2304) kg. Caffeine citrate therapy was initiated at a median (interquartile range) postnatal age of 1 (1 – 3) day and TDM was performed at a postnatal age of 15 (10 – 24) days. No direct correlations were found between respiratory rate or apneic episodes and caffeine serum concentrations; however, heart rate and caffeine serum concentrations were significantly correlated (p < 0.05). Dosing regimen of 40/5 mg/kg q12h (loading dose/maintenance dose, time interval) led to similar endotracheal re-intubation rate but increased percentage of patients experiencing tachycardia compared to the standard regimen of 20/5 mg/kg q24h (44.7 % vs 10.2 %, p < 0.001).

Conclusion

Based on this retrospective study, no correlation between episodes of apnea and caffeine serum concentrations was found in neonates who had TDM of caffeine citrate therapy in the post-extubation period, whereas a significant association between tachycardia and concentrations existed. Notwithstanding the absence of severe adverse reactions, TDM should be considered in critically ill neonates with unexplained adverse effects, such as tachycardia.

Electronic supplementary material

The online version of this article (doi:10.1186/s40360-016-0065-x) contains supplementary material, which is available to authorized users.

Neurodevelopmental Outcomes in Very Low Birth Weight Infants Using Aminophylline for the Treatment of Apnea

BACKGROUND

Aminophylline has been widely used in the treatment of apneic episodes in premature infants. Animal models suggest caution in the use of aminophylline as it may increase the cerebral metabolic rate and decrease the rate of anoxic survival in neonates. This study aimed to evaluate the neurological outcomes in very low birth weight (VLBW) infants treated with aminophylline for apnea in our neonatal intensive care unit.

METHODS

All VLBW infants (body birth weight < 1500 g) admitted to our neonatal intensive care unit between January 2000 and December 2011 were enrolled in this retrospective study. Clinical characteristics and outcomes of these infants were reviewed and recorded. Scores on the Bayley Scales of Infant Development at 6 months, 12 months, and 18 months of corrected age were also recorded. The controls (who did not receive aminophylline) were matched for gestational age with the aminophylline group.

RESULTS

The baseline characteristics of the aminophylline group and the control group were similar. The neurodevelopmental outcomes as well as rates of patent ductus arteriosus, brain injury, severe retinopathy of prematurity, and necrotizing enterocolitis were not significantly different between the two groups. Only bronchopulmonary dysplasia remained significantly higher in the aminophylline group after adjusting for risk factors (48.08% vs. 21.15%; adjusted odds ratio: 12.50; p < 0.001).

CONCLUSION

Aminophylline therapy for apnea of prematurity had no apparent and additional risk on the neurodevelopmental outcomes of VLBW infants at a corrected age of 18 months. Further studies with a larger sample size are needed to confirm the adverse neurological effects of aminophylline treatment.

The Real-World Routine Use of Caffeine Citrate in Preterm Infants: A European Postauthorization Safety Study

BACKGROUND

Caffeine citrate is the treatment of choice for apnea of prematurity (AOP). Regulatory agencies have requested real-world data on drug utilization and safety, a postauthorization safety study, of a pharmaceutical-grade caffeine citrate, Peyona, to confirm its benefit for preterm infants.

OBJECTIVES

To investigate the clinical use, outcomes, and safety profile of this pharmaceutical-grade caffeine citrate in the routine treatment of preterm infants with a gestational age (GA) <37 weeks.

METHODS

We conducted a multicenter, noninterventional, prospective study in five European countries. Patients eligible for study enrollment were <37-week GA neonates who received treatment with the pharmaceutical-grade caffeine citrate and whose parents had given informed consent.

RESULTS

A total of 506 preterm infants were enrolled from 21 institutions. The pharmaceutical-grade caffeine citrate doses were administered intravenously, orally, or via both routes. The main indication of use was AOP treatment (58%) followed by AOP prophylaxis (37%). Median treatment duration was 21 days. The primary cause of study termination was AOP resolution (n = 407; 80%). Hundred and six patients (21%) required supplemental oxygen on day 28; 48 patients (9.5%) had bronchopulmonary dysplasia at 36 weeks' postmenstrual age. Twenty-three adverse drug reactions were observed in 21 neonates (4.2%); the most frequent was tachycardia (2.3%) and only one (seizures) was considered serious. Thirty-one patients (8.1%) had hepatic or renal functional impairment; the side effects were manageable, and these patients also benefitted from treatment.

CONCLUSIONS

The use of this caffeine citrate is safe for the management of AOP in a real-world setting.

Evidence-Based Pharmacologic Therapies for Prevention of Bronchopulmonary Dysplasia: Application of the Grading of Recommendations Assessment, Development, and Evaluation Methodology

Bronchopulmonary dysplasia (BPD) is the most common chronic complication of extreme preterm birth. The authors applied the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology to pharmacologic therapies found to prevent BPD. Caffeine and vitamin A are the only medications shown in high-quality studies to prevent BPD without the risk of clinically important adverse effects. Dexamethasone is effective for the prevention of BPD; but for many infants, the increased risks of hypertrophic cardiomyopathy, gastrointestinal perforation, and cerebral palsy outweigh this benefit. Several medications are currently under investigation for the prevention of BPD, but few are novel agents.

Caffeine therapy in preterm infants

Caffeine is the most commonly used medication for treatment of apnea of prematurity. Its effect has been well established in reducing the frequency of apnea, intermittent hypoxemia, and extubation failure in mechanically ventilated preterm infants. Evidence for additional short-term benefits on reducing the incidence of bronchopulmonary dysplasia and patent ductus arteriosus has also been suggested. Controversies exist among various neonatal intensive care units in terms of drug efficacy compared to other methylxanthines, dosage regimen, time of initiation, duration of therapy, drug safety and value of therapeutic drug monitoring. In the current review, we will summarize the available evidence for the best practice in using caffeine therapy in preterm infants.