Indomethacin and patent ductus arteriosus: effects on renal function in preterm lambs

Multiple courses of indomethacin and neonatal outcomes in premature infants

The objective of this retrospective cohort study was to determine patent ductus arteriosus (PDA) closure rate with multiple short courses (three doses) of postnatal indomethacin and compare neonatal outcomes in infants who received two versus three courses of indomethacin for PDA closure. Infants <34 weeks' gestational age born between January 2000 and December 2004 at the University of Maryland Medical Center and who received two or more short courses of indomethacin were included. Outcome measures were ductal closure rate and neonatal outcomes. Of 61 infants who were identified to have received two or more courses of indomethacin, 26 infants closed their ductus after the second course (response rate, 42%). Of the 35 infants who failed ductal closure after two courses, 11 infants had their ductus ligated and 23 received a third course of indomethacin. Of 23 who received a third course, 10 closed their ductus (response rate, 43%). There was no significant difference in the incidence of chronic lung disease, severe retinopathy of prematurity, necrotizing enterocolitis, renal function, or mortality between infants who received two and those who received three courses of indomethacin. Infants exposed to three courses of indomethacin had a statistically nonsignificant increased incidence of periventricular leukomalacia (p = 0.08; adjusted odds ratio = 4.8; 95% CI, 0.8-30) and remained in the hospital for a longer duration (p = 0.02) compared to infants exposed to two courses of indomethacin. We conclude that multiple courses of indomethacin may be associated with a ductal closure. However, the requirement for a third course may be associated with an increased risk of periventricular leukomalacia.

Neurodevelopmental outcome of premature infants after exposure to antenatal indomethacin

OBJECTIVE

This study was undertaken to evaluate the effect of antenatal indomethacin exposure on neurodevelopmental outcomes of premature infants.

STUDY DESIGN

A retrospective cohort study was performed to compare neurodevelopmental outcomes between premature infants exposed to antenatal indomethacin and infants unexposed to antenatal indomethacin. Inclusion criteria included all 23-29 weeks' gestational age infants delivered between January 1998 and December 2002 who had neurodevelopmental evaluation performed at 16-24 months corrected age. Outborn infants and those with major congenital malformations or chromosomal problems were excluded. Continuous and categorical variables were analyzed by using t test and chi(2) test, respectively.

RESULTS

A total of 255, 23-29 weeks' gestational age infants were delivered between January 1998 and December 2002. Of the 87 infants who met inclusion criteria, 29 infants were exposed to antenatal indomethacin (mean dose 267 mg and median duration 3 days) and 58 infants were unexposed to antenatal indomethacin. There were no significant differences between the 2 groups in clinical characteristics, except for gestational age, mode of delivery, and antenatal steroid exposure. There was no significant difference in major neurosensory abnormality (cerebral palsy and/or deafness and/or blindness); however, the proportion of infants with subnormal Bayley-Mental Developmental Index (70 or less) and neurodevelopmental impairment (neurosensory abnormality and/or Mental Developmental Index 70 or less) was significantly less in the group exposed to antenatal indomethacin compared with unexposed group. When controlled for confounders including antenatal steroids, antenatal indomethacin was not associated with Mental Developmental Index 70 or less (odds ratio 0.44, 95% confidence interval 0.12-1.5) and neurodevelopmental impairment (odds ratio 0.4, 95% confidence interval 0.13-1.2) by using logistic regression. Subgroup analysis of 12 infants exposed to antenatal indomethacin within 48 hours of birth was not associated with neurodevelopmental impairment (odds ratio 0.2, 95% confidence interval 0.03-1.02) compared with unexposed group.

CONCLUSION

Antenatal indomethacin is not associated with abnormal neurodevelopmental outcome in infants 29 or less weeks' gestational age.

Metaanalysis of the effect of antenatal indomethacin on neonatal outcomes

OBJECTIVE

The objective of the study was to determine whether indomethacin used as a tocolytic agent is associated with adverse neonatal outcomes.

STUDY DESIGN

We used published guidelines of the Metaanalysis of Observational Studies in Epidemiology Group (MOOSE) to perform the metaanalysis. The search strategy used included computerized bibliographic searches of MEDLINE (1966-2005), PubMed (1966-2005), abstracts published in Obstetrics and Gynecology (1991-2005), abstracts published in Pediatric Research (1991-2005), and references of published manuscripts. Study inclusion criteria were publication in English, more than 30 deliveries less than 37 weeks' gestation, and meeting diagnostic criteria for individual neonatal outcomes. Exclusion criteria included case reports, case series, and multiple publications from the same author. Metaanalysis was performed using random effects model if there were more than 2 observational studies for a specific outcome. Eggers test was performed to exclude publication bias. Sensitivity analysis was performed to evaluate the effect of antenatal steroid exposure, gestation, and recent antenatal indomethacin exposure (duration of 48 hours or more between the last dose and delivery).

RESULTS

Fifteen retrospective cohort studies and 6 case-controlled studies met inclusion criteria. Antenatal indomethacin was associated with an increased risk of periventricular leukomalacia (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.3-3.1). Recent exposure to antenatal indomethacin was associated with necrotizing enterocolitis (OR, 2.2; 95% CI; 1.1-4.2). Antenatal indomethacin was not associated with intraventricular hemorrhage, patent ductus arteriosus, respiratory distress syndrome, bronchopulmonary dysplasia, and mortality.

CONCLUSION

Antenatal indomethacin may be associated with an increased risk of periventricular leukomalacia and necrotizing enterocolitis in premature infants and therefore should be used judiciously for tocolysis.

Nephrotoxic drugs

The nephrotoxic effects of cyclosporine, aminoglycoside antibiotics, cisplatin, amphotericin B, beta-lactam antibiotics and indomethacin are reviewed. These drugs were chosen because they are among the most frequent causes of renal injury in children. In addition, their nephrotoxicity is caused by different mechanisms. Several generalizations can be made, however. First, agents which cause tubular damage tend to be synergistic in their toxic effects. This synergism is seen when several nephrotoxic drugs are given simultaneously. In addition, the use of a nephrotoxic agent in a patient with pre-existing renal disease can result in severe tubular injury. Second, serum levels of the drug frequently fail to correlate with the degree of nephrotoxicity in individual patients. Third, early signs of renal injury can be subtle (e.g., minor changes in electrolyte excretion) or dramatic (e.g., acute renal failure). The subtle changes are particularly important, since they can be useful predictors of serious nephrotoxicity.