Indomethacin therapy in premature infants with patent ductus arteriosus and oliguria

Furosemide for symptomatic patent ductus arteriosus in indomethacin-treated infants

BACKGROUND

Inhibition of prostaglandin synthesis mediates closure of the ductus arteriosus and renal side effects after indomethacin administration. Because furosemide increases prostaglandin production, it could potentially help prevent indomethacin-related toxicity but also decrease ductal response to indomethacin.

OBJECTIVES

The primary objectives of this review were to assess (1) whether furosemide affects the incidence of failure of ductal closure after indomethacin and that of indomethacin-related toxicity and (2) the effect of furosemide on mid-term and long-term outcome. The secondary objective was to determine whether the effect of furosemide on renal function and water balance depends on prior extracellular volume (assessed by blood urea nitrogen [BUN]/creatinine ratio).

SEARCH STRATEGY

We searched electronic databases (Medline, Embase and Cochrane) and selected abstract books, without language restriction.

SELECTION CRITERIA

We selected studies with (1) random allocation to either indomethacin alone or indomethacin and furosemide and (2) analysis of either short-term risk-benefit ratio of furosemide, mid- or long-term outcome, or the relationship between extracellular volume at study entry and changes in renal function.

DATA COLLECTION AND ANALYSIS

We assessed studies for possible bias and for quality of assessment of ductal patency. We assessed categorical variables using relative risk and absolute risk reduction. We assessed the effects of furosemide on renal function and fluid balance by comparing changes from baseline in the treatment group with those in controls. Subsets were determined a priori based on BUN/creatinine ratio at study entry.

MAIN RESULTS

All 3 studies fulfilling the entry criteria had limitations, including possible or definite bias. There was substantial heterogeneity among studies. Furosemide administration did not significantly increase the risk of failure of ductal closure; however, sample size was insufficient to rule out even a 31% increase. In the subset with initial BUN/creatinine ratio > 20 mg/mg, 2 of 18 patients receiving furosemide could not complete a 3-dose course of indomethacin because of toxicity. Minimal or no information was available about any of the other main outcome variables. Furosemide increased urine output regardless of the initial BUN/creatinine ratio, leading to a 5% weight loss during a 3-dose course, an undesired effect in patients with initial BUN/creatinine ratio > 20 mg/mg. Furosemide increased creatinine clearance only in patients with initial BUN/creatinine ratio <20 mg/mg.

REVIEWER'S CONCLUSIONS

There is not enough evidence to support the administration of furosemide to premature infants treated with indomethacin for symptomatic patent ductus arteriosus. Furosemide appears to be contraindicated in the presence of dehydration in those infants.

The effect of indomethacin tocolysis in preterm labour on perinatal outcome: a randomised placebo-controlled trial

OBJECTIVE

To determine whether indomethacin tocolysis in preterm labour is associated with a better perinatal outcome than placebo.

DESIGN

A randomised placebo-controlled trial.

SETTING

Two university teaching hospitals with level three neonatal intensive care units.

POPULATION

Women in preterm labour with intact membranes between 23 and 30 weeks of gestation.

METHODS

Random allocation to tocolysis with indomethacin (50 mg followed by 25 mg 6 hourly for 48 hours) or placebo in a double-blind fashion.

MAIN OUTCOME MEASURES

The primary outcome, perinatal mortality or severe neonatal morbidity, was defined as perinatal death, necrotising enterocolitis, bronchopulmonary dysplasia, intraventricular haemorrhage or peri-ventricular leucomalacia. Data were analysed using odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

Between March 1995 and February 1996, 34 women (39 babies) were recruited. The baseline characteristics of the two groups were similar. No patient was lost to follow up. In the indomethacin group, gestation was prolonged by > 48 hours in 13/16 (81%) of women vs 10/18 (56%) in the placebo group. The incidence of perinatal mortality or severe neonatal morbidity was not significantly different between the groups, but occurred in twice as many babies in the indomethacin group as in the placebo group--6/19 (32%) vs 3/20 (15%) OR (95% CI) 2.62 (0.44-18.8). There was one perinatal death, of a baby delivered at 24 weeks of gestation. This occurred in the indomethacin group.

CONCLUSION

There is no evidence that indomethacin tocolysis is beneficial, and further trials are needed to assess the impact of indomethacin tocolysis in preterm labour.

Furosemide does not prevent indomethacin-induced renal side effects in preterm infants

OBJECTIVE

To determine whether furosemide could prevent renal side effects of indomethacin (INN, indometacin) used for the pharmacologic closure of the patent ductus arteriosus (PDA) in preterm infants.

METHODS

Thirty-six preterm infants with birth weights < 1750 gm affected by hemodynamically significant PDA were randomly assigned to one of two study groups. Group 1 consisted of 18 infants treated with three doses of indomethacin (0.20 mg/kg every 12 hours); each dose was followed by a dose of furosemide (1 mg/kg). Group 2 consisted of 18 infants treated only with the same doses of indomethacin. Body weight, urine output, glomerular filtration rate (GFR), fractional excretion of sodium (FENa+) and potassium (FEK+), and osmolal and free water clearance were evaluated in both groups before, during, and after treatment.

RESULTS

The body weight trend, serum sodium, chloride and potassium concentrations, plasmatic and urinary osmolality were similar during the treatment in both the groups. A significant reduction of urine output (p < 0.01) was detected in group 2 but not in group 1. A significant increase of blood urea nitrogen and serum creatinine was detected at the end of treatment in group 1 compared with group 2. During the treatment, a significantly higher GFR (p < 0.05) was found in group 2 than in group 1. FENa+ and FEK+ were significantly higher (p < 0.05 and p < 0.001, respectively) in group 1 than in group 2 during and after the treatment. The osmolol clearance and free water clearance were significantly higher during and after treatment (p < 0.01 and p < 0.001, respectively) in group 1 than in group 2.

CONCLUSIONS

Our findings show that furosemide cannot prevent the indomethacin-induced renal failure, but it does not have any negative influence on its therapeutic effectiveness.

Adverse drug reactions in neonates

Adverse drug reactions (ADR) are uncommon causes of admission of neonates to the neonatal intensive care unit. The neonate, however, is potentially at significant risk for adverse drug reactions because of underdeveloped mechanisms and systems for handling drugs (the Gray Baby Syndrome with chloramphenicol as a classic example), the fact that infants in neonatal intensive care units are often critically ill with multiple organ system dysfunction, that they may be on multiple drugs, and that they may present with an adverse drug reaction as a result of exposure while still a fetus. There is also a history of misadventures in the neonatal intensive care unit and newborn nurseries due to exposure to antibacterial agents that produced systemic effects from percutaneous absorption. In this review, an overview of the mechanisms of adverse drug reactions will be presented, followed by a general review of the experience of adverse drug reactions in neonates and some specific examples of current adverse drug reactions and a suggested approach for the prevention and evaluation of adverse drug reactions in neonates.