MODEL-BASED LAMOTRIGINE CLEARANCE CHANGES DURING PREGNANCY: CLINICAL IMPLICATION

In 77% of pregnant women taking lamotrigine, oral clearance increased substantially from a baseline of 2.16 L/h to 6.88 L/h by end of pregnancy (219% increase), at a rate of 0.118 L/h per week of gest

Effect: decline; CL/F increase from 2.16 to 6.88 L/h (219% increase, rate 0.118 L/h/week)

In 23% of pregnant women taking lamotrigine, oral clearance increased only modestly from 2.16 to 2.62 L/h (21% increase) over the course of pregnancy, at a rate of 0.0115 L/h per week -- ten-fold lowe

Effect: null; CL/F increase from 2.16 to 2.62 L/h (21% increase, rate 0.0115 L/h/week)

After delivery, lamotrigine oral clearance declined exponentially back to pre-pregnancy baseline values with a half-life of 0.55 weeks, meaning doses should be tapered to preconception levels within 3

Effect: improvement; CL/F return half-life 0.55 weeks (rate constant k=1.27/week)