Cysteine, cystine or N-acetylcysteine supplementation in parenterally fed neonates.

Study answer

What this study found

Routine cysteine supplementation of cysteine-free PN improved nitrogen balance and plasma cysteine measures, but it did not clearly improve growth. In Zlotkin 1981, weight gain was MD -4.1 g/kg/day (95% CI -9.7 to 1.5), length gain was MD 0 cm/6 days, and nitrogen retention increased WMD 31.8 mg/kg/day (95% CI 8.2 to 55.4). The large extremely low birth weight N-acetylcysteine trial did not show clinical benefit: first-week weight gain MD 0.25 g/kg/day, death by 36 weeks RR 1.23, and no reduction in ROP, NEC, IVH, or PVL; plasma cysteine at end of therapy was slightly lower with…

Study & population

Systematic review and meta-analysis of randomized trials in neonates receiving parenteral nutrition, predominantly preterm, very low birth weight, or extremely low birth weight infants.

Intervention

Randomized trials evaluated short-term parenteral supplementation of neonatal PN with cysteine or cystine, most commonly as cysteine hydrochloride at about 0.46 to 1.0 mmol/kg/day for 6 days or similar brief courses.

Key limitation

Most contributing trials were small and short in duration, with heterogeneous formulations, doses, and comparators.

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Original abstract