Lamotrigine has become the most frequently prescribed drug in the treatment of pregnant women with epilepsy. Although some relevant studies have found a wide milk/maternal serum as well as infant/maternal serum concentration ratio, different infant ages at the time of sampling and small number of patients preclude comparison. The aim of this study was to provide a consistent evaluation.
Data of 43 nursing women treated by lamotrigine were evaluated retrospectively. The authors followed the transport of lamotrigine during the first postnatal month from mothers to breastfed infants through maternal milk between the years 2002 and 2017.
Lamotrigine concentrations varied from 1.1 to 14.9 mg/L in the maternal serum, from <0.66 to 9.1 mg/L in the milk and between <0.66 and 6.9 mg/L in the infant serum. The milk/maternal serum concentration ratio ranged from <0.18 to 0.74 and the infant/maternal serum concentration ratio measured between <0.15 and 0.74. Highly significant correlations were found between milk and maternal serum levels and between infant serum levels and milk, maternal serum levels, lamotrigine daily dose, and also maternal dose related to the body weight.
The authors confirmed the wide range of the milk/maternal serum concentration ratio and the infant/maternal serum concentration ratio. Although the degree of lamotrigine exposure to the breastfed infants was smaller than during gestation, 16% of the infant serum levels measured were within the therapeutic range used for the general epileptic population. Lamotrigine concentration monitoring in breastfed infant, in our opinion, is the most relevant aspect for the analysis of actual lamotrigine exposure in infants, especially in those with clinical symptoms.
*Department of Clinical Pharmacology, Faculty of Medicine, University of Ostrava; and
†Department of Clinical Pharmacology and Laboratory Diagnostics, University Hospital Ostrava, Ostrava, Czech Republic.
Correspondence: Milan Grundmann, MD, PhD, Department of Clinical Pharmacology, Faculty of Medicine, University of Ostrava, Syllabova 19, 703 00 Ostrava, Czech Republic (e-mail: firstname.lastname@example.org).
The authors declare no conflict of interest.
Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.drug-monitoring.com).
Received September 07, 2018
Accepted November 13, 2018