Relative Bioavailability of Carnitine Supplementation in Premature Neonates

• Published in: JPEN. Journal of parenteral and enteral nutrition 2006-09, Vol.30 (5), p.421-425
• Main Authors: Crill, Catherine M., Christensen, Michael L., Storm, Michael C., Helms, Richard A.
• Format: Article
• Language: English
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Biological Availability; Carnitine - pharmacokinetics; Dietary Supplements; Diseases of mother, fetus and pregnancy; Emergency and intensive care: metabolism and nutrition disorders. Enteral and parenteral nutrition; Enteral Nutrition; Female; General and cellular metabolism. Vitamins; Gynecology. Andrology. Obstetrics; Humans; Infant, Newborn; Infant, Premature - metabolism; Intensive care medicine; Male; Medical sciences; Parenteral Nutrition; Pharmacology. Drug treatments; Pregnancy. Fetus. Placenta; Treatment Outcome; Vitamin B Complex - pharmacokinetics
• ISSN: 0148-6071; 1941-2444
• DOI: 10.1177/0148607106030005421

Background: Carnitine is an important nutrient in the infant diet. We compared total plasma carnitine concentrations in premature neonates supplemented with carnitine via parenteral and enteral nutrition. Methods: This is a post hoc analysis of plasma total carnitine concentrations and carnitine intake in neonates randomized in a previous study to receive 20 mg/kg/d carnitine supplementation over 8 weeks. Neonates received l-carnitine initially via parenteral nutrition (PN). When neonates were fed enterally, oral supplementation of l-carnitine was given in divided doses with each feeding. Results: Sixteen neonates (27 ± 2 weeks gestation; 2.9± 1.0 days postnatal age at enrollment; 965.6 ± 279.1 g birth weight) are included. Concentrations were below reference range (31.1–60.5 nmol/mL) at baseline and exceeded reference range from week 1 through the last study period. Concentrations were not different from week 1 (108 ± 49) through weeks 4 (87 ± 34) and 8 (83 ± 31). Carnitine intakes and concentrations were compared in neonates receiving 100% parenteral carnitine at week 1 (n = 6) and 100% enteral carnitine at week 8 (n = 8). Concentrations at week 1 (100.1 ± 27.9) were not different (p = .19) from week 8 (78.6 ± 29.3); an estimate of relative bioavailability was 78.6%. Bioavailability with paired analysis of neonates (n = 5) receiving 100% parenteral carnitine at week 1 and 100% enteral carnitine at week 8 was 83.7% ± 41.2% (30.1%–140.6%). Conclusions: Parenteral and enteral supplementation of 20 mg/kg/d carnitine results in plasma total carnitine concentrations that exceed the reference range. Concentrations are not different between parenteral to enteral supplementation, suggesting that enteral carnitine is well absorbed when given daily in divided doses with enteral feedings. This study evaluated total plasma carnitine concentrations in preterm neonates supplemented with 20 mg/kg/d via parenteral and enteral nutrition. Supplementation of oral carnitine in divided doses with enteral feedings results in total plasma carnitine concentrations similar to those seen with parenteral carnitine supplementation, suggesting a relative bioavailability of approximately 80%.