The effect of caffeine compared with theophylline in the treatment of idiopathic apnea in premature infants

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 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.

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

Apnea of prematurity (AOP) is a common complication of preterm birth, which affects more than 80 % of neonates with a birth weight less than 1,000 g. Methylxanthine therapies, including caffeine and theophylline, are a mainstay in the treatment and prevention of AOP. Despite their frequent use, little is known about the long-term safety and efficacy of these medications. In this review, we systematically evaluated the literature on neonatal methylxanthine therapies and found that caffeine is associated with fewer adverse effects and a wider therapeutic window when compared with theophylline. When used as a therapeutic agent, larger doses of caffeine citrate have been shown to improve acute neonatal outcomes when administered promptly, although further studies are needed to assess the long-term neurological consequences associated with the use of large loading doses. In a secondary analysis of data obtained from a randomized controlled trial, the prophylactic use of caffeine was associated with substantial cost savings and improved clinical outcomes. However, there remains a paucity of well-controlled, randomized clinical trials that have examined the use of caffeine as a prophylactic agent, and further prospective trials are needed to determine if caffeine is a safe and effective prophylactic agent. Additionally, measuring plasma concentrations longitudinally as a marker of therapeutic efficacy and/or toxicity has not been shown to be clinically useful in neonates who are responsive to treatment and exhibit no signs or symptoms of toxicity. However, in cases where toxicity is of concern or for neonates with congenital or pathophysiologic process that may alter the pharmacokinetics of these drugs, therapeutic drug monitoring may be warranted to monitor for methylxanthine toxicity.

Caffeine versus theophylline for apnea in preterm infants

BACKGROUND

Recurrent apnea is common in preterm infants, particularly at very early gestational ages. These episodes of loss of effective breathing can lead to hypoxemia and bradycardia, which may be severe enough to require resuscitation including use of positive pressure ventilation. Two forms of methylxanthine (caffeine and theophylline) have been used to stimulate breathing in order to prevent apnea and its consequences.

OBJECTIVES

To evaluate the effect of caffeine compared with theophylline treatment on the risk of apnea and use of mechanical ventilation in preterm infants with recurrent apnea.

SEARCH STRATEGY

The standard search strategy of the Cochrane Neonatal Review Group was used. This included searches of electronic databases in August 2009: Oxford Database of Perinatal Trials; Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2009); MEDLINE (1966 to April 2009); and EMBASE Drugs and Pharmacology (1990 to April 2009), previous reviews including cross references.

SELECTION CRITERIA

Randomized and quasi-randomized trials comparing caffeine to theophylline for treating apnea in preterm infants and reporting effects on apnea event rates.

DATA COLLECTION AND ANALYSIS

Each author assessed eligibility and trial quality, extracted data separately and compared and resolved differences. Study authors were contacted for additional information.

MAIN RESULTS

Five trials involving a total of 108 infants were included. The quality of most of these small trials was fair to good. No difference in treatment failure rate (less than 50% reduction in apnea/bradycardia) was found between caffeine and theophylline after one to three days treatment (based on two studies) or five to seven days treatment (based on one study). There was no difference in mean apnea rate between caffeine and theophylline groups after one to three days treatment (based on five trials) and five to seven days treatment (based on four trials).Adverse effects, indicated by tachycardia or feed intolerance leading to change in dosing, were lower in the caffeine group (summary relative risk 0.17, 95% CI 0.04 to 0.72). This was reported and consistent in three studies.No trial reported the use of ventilation and no data were available to assess effects on growth and development.

AUTHORS' CONCLUSIONS

Caffeine appears to have similar short-term effects on apnea/bradycardia as does theophylline although caffeine has certain therapeutic advantages over theophylline. Theophylline is associated with higher rates of toxicity. The possibility that higher doses of caffeine might be more effective in extremely preterm infants needs further evaluation in randomized clinical trials.

Caffeine in apnoeic Asian neonates: a sparse data analysis

AIMS

To monitor plasma caffeine concentrations and adverse effects and to study the pharmacokinetics of caffeine in neonatal apnoea in the local Asian population after intravenous administration of caffeine.

METHODS

Eighteen neonates with apnoea were treated with caffeine citrate at a loading dose of 10 mg caffeine base kg-1 and a maintenance dose of 2.5 mg kg-1 day-1. Blood samples, three after loading and two after the maintenance dose on day 2, 3, 7, 14 and 21 were taken and analysed for caffeine and its main metabolites using solid phase extraction and h.p.l.c. Adverse effects were monitored. Sparse data pharmacokinetic analysis was performed using P-Pharm.

RESULTS

Mean caffeine concentrations varied from 10 to 20 mg l-1 throughout treatment (range 3.6-28.4 mg l-1). These concentrations were efficacious; less so in those with lower concentrations. Adverse effects included gastrointestinal disturbances, diuresis and hyperglycaemia. Pharmacokinetic parameter estimates [mean (coefficient of variation%)] were CL=0.00628 (17.5%) l h-1 and V=0.961 (20.3%) l. CL (l h-1)=0.004248 * wt(kg)+0.00154; r=0.8, P<0.01, explained 64% of the variation. V (l)=0.6299 * wt(kg)+0.259; r=0.67, P<0.01, explained 45% of variation. Model-predicted compared with observed plasma concentrations in a separate group of 10 neonates were unbiased and of good precision.

CONCLUSIONS

The dosing regimen studied was suitable for our local Asian neonates as it resulted in therapeutic caffeine concentrations for adequate treatment of apnoea. Adverse effects were tolerable. Therefore, to avoid a higher incidence of adverse effects, this regimen should be retained and not increased as proposed by other workers. CL and V were within values of those reported for neonatal apnoea. Sparse data analysis showed that weight alone was adequate as the influential variable for the accurate prediction of individual pharmacokinetic parameters, plasma concentrations and for dosage adjustment if required.

Caffeine citrate: a review of its use in apnoea of prematurity

Apnoea of prematurity is a common condition in neonates born at less than 37 weeks' gestational age; it affects approximately 90% of premature neonates weighing under 1000 g at birth, and 25% of infants with a birthweight of less than 2500 g. Caffeine, a methylxanthine which occurs naturally in many plants, has been used for over 20 years to treat apnoea of prematurity. In a recent double-blind, placebo-controlled trial, apnoea was eliminated or reduced by at least 50% in significantly more neonates receiving caffeine citrate as first-line treatment than those receiving placebo. In a nonblind trial, caffeine citrate was more effective at reducing apnoeic episodes when compared with neonates receiving no treatment. Caffeine as first-line treatment demonstrated similar efficacy to theophylline or aminophylline (theophylline ethylenediamine) in 4 small randomised studies. Caffeine citrate was generally well tolerated in short term clinical trials, with very few adverse events reported. Caffeine was associated with fewer adverse events than theophylline in randomised trials. No differences in the incidence of individual adverse events were reported between caffeine citrate and placebo in a double-blind, randomised trial. Long term tolerability data are not yet available.

CONCLUSIONS

Caffeine citrate was generally well tolerated by neonates in clinical trials and it decreased the incidence of apnoea of prematurity compared with placebo. It has demonstrated similar efficacy to theophylline, but is generally better tolerated and has a wider therapeutic index. Caffeine citrate should, therefore, be considered the drug of choice when pharmacological treatment of apnoea of prematurity is required.

Risks and benefits of therapies for apnoea in premature infants

Apnoea in infants can result from a wide range of causes, and requires thorough evaluation before deciding on appropriate treatment. Continuous monitoring of premature infants with apnoea is mandatory in order to define the pathophysiology and type of apnoea; selection of treatment involves careful assessment of aetiology, as well as efficacy and tolerability in each individual case. The objective of treatment is to prevent the deleterious consequences of apnoeas that last >20 seconds and/or are associated with bradycardia, cyanosis or pallor, and occur more often than once an hour over a 12-hour period. Apnoea management involves both pharmacological and nonpharmacological treatment. We suggest methylxanthines as first-line therapy for idiopathic apnoeas; evidence suggests that caffeine is better tolerated and as efficacious as theophylline (since it is particularly efficacious against the 'central' component of idiopathic apnoea of prematurity). If treatment fails, additional measures such as doxapram may be appropriate when hypoventilation is present, or nasal continuous positive airway pressure when upper airway instability or obstructive apnoeas are predominant. Apnoea prophylaxis is an additional reason to advocate prenatal maturation with betamethasone. Weaning from treatment is attempted 4 to 5 days after complete resolution of apnoea, beginning with the last treatment introduced. Monitoring should be maintained for 4 to 5 days to detect any relapse of recurrent and severe apnoeas, which would lead to the resumption of the most recently withdrawn treatment.

Caffeine citrate for the treatment of apnea of prematurity: a double-blind, placebo-controlled study

STUDY OBJECTIVE

To evaluate the efficacy and safety of caffeine citrate for treatment of apnea of prematurity.

DESIGN

Multicenter, parallel, randomized, double-blind, placebo-controlled trial with open-label rescue.

SETTING

Nine neonatal intensive care units.

PATIENTS

Eighty-five infants, 28-32 weeks postconception and 24 hours or more after birth who had six or more apnea episodes within 24 hours.

INTERVENTION

Caffeine citrate 10 mg/kg (as caffeine base) administered intravenously, followed by 2.5 mg/kg/day orally or intravenously, or placebo, for up to 10 days. Infants failing double-blind therapy could receive open-label rescue.

MEASUREMENTS AND MAIN RESULTS

Success was defined as 50% or greater reduction in apnea episodes and elimination of apnea. Caffeine citrate was significantly more effective than placebo in reducing apnea episodes by at least 50% in 6 days (p<0.05), and approached statistical significance (p<0.10) in 3 days. It was significantly better than placebo in eliminating apnea in 5 days (p<0.05), and approached significance (p<0.10) in 2 days. The number of infants with an aggregate of 7-10 days of at least a 50% reduction in apnea events or elimination of apnea was significantly higher in the caffeine citrate than in the placebo group. Adverse events did not differ significantly between groups. No correlations were found between success and mean daily plasma concentrations or baseline characteristics. Volume of distribution and clearance increased with weight, supporting weight-adjusted dosing of caffeine citrate.

CONCLUSION

Caffeine citrate 10 mg/kg caffeine base (equivalent to 20 mg/kg caffeine citrate) intravenously followed by 2.5 mg/kg/day caffeine base (equivalent to 5 mg/kg/day caffeine citrate) either intravenously or orally for 10 days is safe and effective for treating apnea of prematurity in infants 28-32 weeks postconception.

Current options in the management of apnea of prematurity

Apnea of prematurity (AOP) is a common problem that affects premature infants and, to a lesser degree, term infants. Apnea of prematurity appears to be due to immaturity of the infant's neurologic and respiratory systems. Apnea of prematurity is a diagnosis of exclusion that can be made only when other possible infectious, cardiologic, physiologic, and metabolic causes of apnea have been ruled out. The fundamental principles for managing apnea of prematurity include monitoring the infant closely while instituting supportive care measures such as tactile stimulation, continuous positive airway pressure, or mechanical ventilation. When necessary, pharmacologic therapy may be used to stimulate breathing. The first-line agents of choice for the management of AOP are the methylxanthines. And, for second-line therapy, a switch to a different class of agent, such as the respiratory stimulant doxapram, is an option. Of the methylxanthines, theophylline is the most extensively used. However, a review of the literature suggests that caffeine citrate may be the agent of choice for AOP. Comparative clinical studies have demonstrated that caffeine is at least as effective as theophylline, has a longer half-life, is associated with fewer adverse events, and, in addition, has a greater ease of administration. Caffeine stimulates the respiratory and central nervous systems more effectively and penetrates into the cerebrospinal fluid more readily than theophylline. In addition, because of stable plasma levels, caffeine has a wide therapeutic margin and few side effects. In contrast, theophylline plasma levels may fluctuate widely, which necessitates frequent monitoring and has a higher incidence of adverse events than caffeine. Before the FDA approval of caffeine citrate (Cafcit) for administration either intravenously and/or orally, caffeine preparations were "homemade." A few studies suggest that use of pharmacotherapy to treat AOP is not generally associated with long-term sequelae, although more data are needed before this can be definitively concluded.

Caffeine versus theophylline for apnea in preterm infants

BACKGROUND

Recurrent apnea is common in preterm infants, particularly at very early gestational ages. These episodes of loss of effective breathing can lead to hypoxemia and bradycardia which may be severe enough to require resuscitation including use of positive pressure ventilation. Two forms of methylxanthine (caffeine and theophylline) have been used to stimulate breathing and so prevent apnea and its consequences.

OBJECTIVES

In preterm infants with recurrent apnea, does caffeine treatment compared to theophylline treatment lead to a clinically important reduction in apnea and use of mechanical ventilation without clinically important side effects?

SEARCH STRATEGY

Standard strategies of the Neonatal Review Group were used. Searches were made of the Oxford Database of Perinatal Trials, MEDLINE (see main text for strategy), previous reviews including cross references, abstracts conferences and symposium proceedings, expert informants, journal handsearching mainly in the English language. Also an expert informant's search in the Japanese language was made by Prof Y. Ogawa.

SELECTION CRITERIA

All trials utilising random or quasi-random patient allocation in which caffeine was compared with theophylline for the treatment of apnea were eligible. Trial quality and eligibility were assessed independently by each author. There must have been an effort to exclude specific causes of apnea. Measures of the severity of apnea as well as the response to treatment must have been consistent with an evaluation of 'clinical apnea' as defined by the American Academy of Pediatrics (Nelson 1978).

DATA COLLECTION AND ANALYSIS

Standard method of Neonatal Review Group was used. Each author assessed eligibility, trial quality and extracted data separately, then compared and resolved differences. Results are expressed as relative risk (RR) and risk difference (RD). From 1/RD the number needed to treat (NNT) was calculated.

MAIN RESULTS

There is no difference in the failure rate (< 50% reduction in apnea/bradycardia) of treatment with caffeine or theophylline at 1-3 (two studies) or 5-7 days (one study). There is a higher mean rate of apnea in the standard caffeine group at 1-3 days [three studies, mean diff. 0.398 (0.334,0.463) /100min] but not at 5-7 days (two studies). Side effects, as indicated by tachycardia or feed intolerance leading to change in dosing, are lower in the caffeine group [typical RR 0.17 (0.04,0.72), RD -0.285 (-0.467,-0.104), NNT 3.5 (2.1, 9.6)]. This was consistent across the three studies. No trial reported the use of IPPV and no data are available to assess effects on growth and development.

REVIEWER'S CONCLUSIONS

Caffeine appears to have similar short term effects on apnea/bradycardia to theophylline. In view of the other therapeutic advantages of caffeine (a higher therapeutic ratio, more reliable enteral absorption and a longer half life) this is the preferred treatment for apnea in preterm infants. The possibility that higher doses of caffeine might be more effective in extremely preterm infants needs further evaluation in randomized clinical trials.

Aminophylline versus caffeine citrate for apnea and bradycardia prophylaxis in premature neonates

We investigated the efficacy and adverse effects of aminophylline and caffeine citrate in 180 premature neonates for 10 days and nights. Aminophylline (n = 98) and caffeine citrate (n = 82) were equally effective in preventing apnea and bradycardia. The caffeine citrate group had a lower median heart rate on day 3, fewer neonates with tachycardia and a smaller amount of gastric aspirate on day 7. The need for mononasal continuous positive airway pressure and respirator therapy was similar in both groups. We conclude that caffeine citrate is the drug of choice for apnea and bradycardia prophylaxis in premature neonates with a gestational age < or = 33 full weeks.

An update on research with coffee/caffeine (1989-1990)

The interest in research with coffee has been increasing in recent years, and this has resulted in a surge of publications dealing with a variety of pharmaco-physiological effects of coffee/caffeine. This review attempts to update the information on the research with coffee/caffeine, including epidemiological studies, laboratory investigations and tests with volunteers, published in 1989 and 1990. It groups published articles according to observed or investigated biological effects. The most significant findings and differences between studies are pointed out with brief commentaries on the results. The overall assessment for the safety of drinking coffee and the effect of coffee on human health, based on the literature published in 1989 and 1990, indicates that certain controversial issues are still unresolved.

The effects of postnatal caffeine exposure on growth, activity and learning in rats

Caffeine is both ingested by pregnant women in their third trimesters and administered therapeutically to premature infants to stimulate respiration. This experiment attempted to delineate any persistent effects of low dose caffeine exposure during the first week of life in rats, since this time period provides an animal model equivalent to the human third trimester or premature infant exposure. Rat pups who had received either 1 or 9 mg/kg of caffeine during the first week of life grew more slowly, were hypoactive at two weeks of age, and were impaired on an operant spatial learning task as adults. Adding visual cues to the operant task did not improve their performance. The timing of the appearance of developmental landmarks, adult body weight and adult brain weight, however, were not affected by postnatal caffeine exposure. The persistent behavioral deficits noted after postnatal caffeine exposure were all opposite in direction to the acute effects of caffeine, and similar to the effects of adenosine. Thus the behavioral deficits reported here may reflect an upregulation of developing adenosine receptors that persists into adulthood subsequent to early chronic postnatal caffeine exposure.