Transfer of lamotrigine into breast milk

School of Medicine and Pharmacology, University of Western Australia, Perth City, Western Australia, Australia
Annals of Pharmacotherapy (Impact Factor: 2.06). 07/2006; 40(7-8):1470-1. DOI: 10.1345/aph.1G667
Source: PubMed


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    ABSTRACT: Although lamotrigine use during pregnancy has substantially increased over the past decade secondary to accumulated reproductive safety data, systematic data on lamotrigine during breastfeeding remains sparse. We sought to characterize the determinants of lamotrigine concentrations in breast milk and nursing-infant plasma. Women who enrolled in a prospective investigation of perinatal medication pharmacokinetics, were treated with lamotrigine, and chose to continue lamotrigine while breastfeeding were included in the analysis. Breast milk samples were collected via breast pump from foremilk to hindmilk from a single breast to determine the excretion gradient and serial samples over 24 hours to determine the time course of excretion. Paired maternal/infant plasma samples were also collected. Lamotrigine concentrations in all of the samples were determined by using high-performance liquid chromatography with ultraviolet detection. Statistical analyses of breast milk and infant plasma concentrations and their determinants were conducted. Thirty women and their nursing infants participated in the study, providing a total of 210 breast milk samples. The mean milk/plasma ratio was 41.3%. There was a nonsignificant trend for higher lamotrigine concentrations in breast milk 4 hours after the maternal dose. Infant plasma concentrations were 18.3% of maternal plasma concentrations. The theoretical infant lamotrigine dose was 0.51 mg/kg per day, and the relative infant lamotrigine dose was 9.2%. Mild thrombocytosis was present in 7 of 8 infants at the time of serum sampling. No other adverse events were observed or reported in the breastfed infants. Consistent with previous investigations of medications in breast milk, the lamotrigine milk/plasma ratio is highly variable. The rate of lamotrigine excretion into human breast milk is similar to that observed with other antiepileptic drugs. These data expand the extant literature on lamotrigine in breastfeeding and demonstrate relatively comparable nursing-infant exposure to lamotrigine compared with other antiepileptic drugs.
    PEDIATRICS 08/2008; 122(1):e223-31. DOI:10.1542/peds.2007-3812 · 5.47 Impact Factor
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    ABSTRACT: To prospectively analyse the pharmacokinetics of lamotrigine (LTG) during pregnancy and lactation in a consecutive series of epileptic pregnant women. Nine women on LTG-monotherapy were studied during pregnancy, delivery and lactation, until a mean of 3 weeks postpartum. Maternal blood samples were available from all trimesters as well as umbilical cord blood samples of the newborn 24 and/or 48 h postpartum. In 4 cases we additionally determined the LTG-concentration in breast milk. The median LTG-clearance was elevated by 197% during the first trimester, 236% and 248% during the second and third trimester respectively. A maximum of 264% was reached at delivery. An average LTG-dose increase by 250% had to be undertaken in order to obtain therapeutic serum levels. In puerperium LTG-clearance decreased again to reach the initial concentrations approximately at the third week postpartum. The median LTG-concentration ratio of the umbilical cord blood to maternal serum was 1.01 (range: 0.56-1.42), while the median LTG-concentration ratio of breast milk to maternal serum was 0.59 (range: 0.35-0.86). Our study confirms the therapeutic relevant changes of LTG-clearance during pregnancy and lactation in women on LTG-monotherapy. Since LTG crosses the placenta, a close monitoring of both mother and newborn is indispensable.
    Epilepsy research 04/2009; 85(1):60-4. DOI:10.1016/j.eplepsyres.2009.02.011 · 2.02 Impact Factor
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