1840 – Pharmacokinetics of lithium during delivery and in the neonatal period. A preliminary data

Abstract

Lithium has been used in the treatment of bipolar disorder in pregnant women. However, information on the pharmacokinetics of lithium during perinatal period is scarce. To study pharmacokinetics of lithium during delivery and in the neonatal period. A prospective, observational and naturalistic study was conducted at the PERINATAL PSYCHIATRY PROGRAM CLÍNIC-BARCELONA, from 2005 to 2012. We included all consecutive cases of pregnant women with bipolar disorder I or II (n = 22), and on maintenance treatment with lithium monotherapy (n = 13) or polytherapy (n = 9) during pregnancy who elected artificial feeding. Lithium plasma concentrations in maternal blood and umbilical cord were detected. Lithium plasma concentrations in infants (n = 16) at delivery and in the neonatal period were obtained to calculate elimination half-life, which was estimated by lineal regression. Technique: AVL 9180 electrolyte analyser using a lithium-selective electrode (detection limit =0.10 mEq/L). Women did not fulfil diabetes criteria pre-pregnancy and during pregnancy. Attending to neonatal outcomes, infants exposed to polytherapy had a higher weight at birth (percentils) than those exposed to lithium alone [53.38 (33.40) vs. 70.22 (26.25)]. No statistically significant differences were found in umbilical cord:maternal plasma concentration ratio between those treated with lithium monotherapy and women treated with polytherapy (1.05 vs. 1.08). The lithium mean elimination half-life (SD) in infants was 6.73 (9.12) days. Lithium crosses placental barrier almost completely. Elimination half-life in neonates exposed to lithium in utero was 6.73 days. Moreover, lithium treatment during pregnancy requires therapeutics monitoring in exposed dyads.