Lamotrigine

An antiepileptic and sodium channel blocker which suppresses the release of glutamate. Indicated in epilepsies and prevention of depression from bipolar disorder type I ^{(AEMPS 2018, GSK 2014)}. Its use is authorized in children from 2 years old. Oral administration (100 to 500 mg/day) in one or two daily doses. Therapeutic plasma levels vary between 2.5 and 15 mg/L. ^{(Mercadé 2012, Aldaz 2011, Morris 1998)} 

It is excreted in breastmilk in amounts which could be significant, with relatively high doses, between 9% and 20%. ^{(Kohn 2022 & 2016, Domínguez 2015, Meador 2014, Sachs 2013, Fotopoulou 2009, Nordmo 2009, Newport 2008, Ivana 2007 , Page 2006, Ohman 2000, Rambeck 1997, Tomson 1997)}

In the short and long term, no side effects or alterations in physical and neurological development have been observed in dozens of infants whose mothers were treated with lamotrigine ^{(Kohn 2022, Levesque 2017, Prakash 2016, Domínguez 2015, Grover 2015, Meador 2014 and 2010, Veiby 2013, Wakil 2009, Newport 2008, Page 2006, Gentile 2005, Liporace 2004, Ohman 2000, Rambeck 1997, Tomson 1997)}, including mothers of premature babies ^{(Précourt 2011)}, which is why several medical associations, experts and expert consensus consider the use of this medication to be compatible or possible with breastfeeding ^{(Hale, Uguz 2021, Birnbaum 2020, Cabo 2019, Vajda 2014, Davanzo 2013, Veiby 2013, Rowe 2013, Mercadé 2012, Précourt 2011, Madadi 2010)}, and it is not necessary to halt breastfeeding if a mother requires lamotrigine, especially if the daily 500mg dose is not exceeded. ^{(Yashima 2021, Kohn 2016)}

Plasma levels in infants whose mothers take lamotrigine are close to the lower therapeutic range and even within it. ^{(Kacirova 2019, Clark 2013, Kacirova 2011, Fotopoulou 2009, Nordmo 2009, Ivana 2007, Page 2006, Liporace 2004, Ohman 2000, Rambeck 1997, Tomson 1997)} 

At birth, infant plasma levels are 60% - 90% of those of the mother, falling after a few weeks to 30% - 50% of maternal levels, indicating that exposure during breastfeeding is much lower than during pregnancy. ^{(Kacirova 2022, Birnbaum 2020, Clark 2013, Newport 2008, Ivana 2007, Page 2006, Liporace 2004)}

During pregnancy the clearance of lamotrigine and other antiepileptic drugs increases, reducing plasma levels, which is why the dose must be increased ^{(Harden 2009, Sabers 2009, Petrenaite 2005, de Haan 2004)}. After childbirth levels increase rapidly and can cause problems for mother and newborn if maternal plasma levels are not monitored by reducing the maternal dose to the previous one before pregnancy. ^{(Paulzen 2018, Fotopoulou 2009, Nordmo 2009, O'Connor 2009, Haan 2004, Ohman 2000, Tomson 1997)}

Sedation, hypotonia and no-weight gain have been observed in up to 4.5% of infants whose mothers were taking this medication (Soussan 2014), especially in the neonatal period. An apnea crisis was reported in a 16-day-old infant whose mother was taking a high dose (850 mg/day) of lamotrigine (Nordmo 2009), anemia was reported in a 40-day-old infant possibly due to maternal lamotrigine (Bedussi 2018), asymptomatic thrombocytosis (Newport 2008) and self-limited exanthem (Wakil 2009).

We have been informed (not published) of a case of a 13-day-old infant with marked drowsiness and hypotonia, with exclusive breastfeeding (direct and expressed due to drowsiness) and good weight gain, whose mother was taking 400 mg of lamotrigine daily and had plasma levels of 13.4 mg/L (in high therapeutic range). The symptomatology disappeared after halting breastfeeding for 48 hours.

A published case of severe hypernatremic dehydration in a 12-day newborn is not easily attributable to maternal lamotrigine. The mother, who had bipolar disorder, was also taking sertraline, aripripazole (which can cause hypogalactia), levothyroxine, naproxen, docusate, acetaminophen and codeine. ^{(Morin 2017)}

An infant of a month and a half whose mother was taking lamotrigine had withdrawal syndrome when she was abruptly weaned. ^{(Popescu 2005)}

Lamotrigine levels in the mother and the neonate should be measured and possible side effects in the neonatal period should be monitored: sedation, poor diet ^{(Kacirova 2022 & 2019, Paulzen 2019, Crettenand 2018, Briggs 2017, Reimers 2014, Davanzo 2013, Rowe 2013, Précourt 2011, Madadi 2010, Ivana 2007, Pack 2006, Crawford 2005, Liporace 2004)}, and the maternal dose can be reduced to a minimum effective dose and/or temporarily establishing partial breastfeeding ^{(Kohn 2022, O'Brien 2005)} if the levels reach the therapeutic range.

See below the information of these related products:

• Maternal Epilepsy (Fairly safe. Mild or unlikely adverse effects. Compatible under certain circumstances. Follow-up recommended. Read Commentary.)
• Maternal Psychotic Disorder. Maternal psychosis, schizophrenia, bipolar disorder (Fairly safe. Mild or unlikely adverse effects. Compatible under certain circumstances. Follow-up recommended. Read Commentary.)