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Finding
Finding
decline
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 gestation, potentially leading to subtherapeutic drug levels and increased seizure risk.
| Effect size | CL/F increase from 2.16 to 6.88 L/h (219% increase, rate 0.118 L/h/week) |
| Comparator | Pre-pregnancy baseline lamotrigine oral clearance (CLBL = 2.16 L/h, between-subject variability 40.6%) |
| Effect summary | decline; CL/F increase from 2.16 to 6.88 L/h (219% increase, rate 0.118 L/h/week) |
| Effect modifiers | [{"modifier": "subpopulation membership (fast vs slow clearance group)", "interaction_p": "", "direction": "reverses", "stratum_details": "Population I (77%): slope 0.118 L/h/week, 219% increase by term; Population II (23%): slope 0.0115 L/h/week, 21% increase by term. Ten-fold difference in rate.", "plain_language": "About 3 in 4 women had a dramatic increase in how fast their body cleared lamotrigine during pregnancy, while 1 in 4 had only a small change. Unfortunately, there is no way to predict which group you will fall into before pregnancy.", "annotation_notes": "Mixture model identified two subpopulations. No covariates (weight, age, race, indication) could distinguish the groups. Women with two pregnancies fell into same group both times."}, {"modifier": "body weight", "interaction_p": "p>0.05", "direction": "null", "stratum_details": "Maternal body weight had no effect on any portion of the clearance model (chi-square test, p>0.05, df=1)", "plain_language": "How much weight you gained during pregnancy did not affect how fast your body cleared lamotrigine.", "annotation_notes": "Consistent with Pennell et al study finding weight-independence"}, {"modifier": "maternal age", "interaction_p": "p>0.05", "direction": "null", "stratum_details": "Age had no significant effect on LTG oral CL (chi-square, p>0.05, df=1). Study population age range 17-42 years.", "plain_language": "Your age did not affect how pregnancy changed your lamotrigine levels, though all women were of childbearing age (17-42).", "annotation_notes": "Narrow age range may explain lack of age effect"}, {"modifier": "clinical indication (epilepsy vs psychiatric)", "interaction_p": "p>0.05", "direction": "null", "stratum_details": "Indication (epilepsy or no epilepsy) had no effect on clearance model (chi-square, p>0.05, df=1)", "plain_language": "Whether you take lamotrigine for epilepsy or for a mood disorder did not change how pregnancy affected your drug levels.", "annotation_notes": "43 pregnancies in epilepsy, 19 in psychiatric, 2 in both"}, {"modifier": "race", "interaction_p": "p>0.05", "direction": "null", "stratum_details": "Race had no effect on any portion of the clearance model (chi-square, p>0.05, df=1)", "plain_language": "Racial background did not change how pregnancy affected lamotrigine clearance in this study.", "annotation_notes": ""}] |
Connected entities
Interventions
Conditions
Populations
Source
PMC4038031
MODEL-BASED LAMOTRIGINE CLEARANCE CHANGES DURING PREGNANCY: CLINICAL IMPLICATION