Pharmacokinetics of Quetiapine Across Pregnancy and Postpartum

Overview

The widespread and common use of quetiapine in childbearing and pregnant women demands more data to inform dosing and toxicity in pregnancy. The new FDA Pregnancy and Lactation Labeling Final Rule (PLLR) will go into effect on June 30th, 2015 and will replace the prior A, B, C, D, and X categories. Additionally, the PLLR will require information to aid prescribing decisions in three categories 1) Pregnancy (including labor and delivery), 2) Lactation, and 3) Females and Males of Reproductive Potential. The pregnancy category will include a subsection that will describe pharmacokinetic and pharmacodynamic characteristics of the medication in pregnancy, fetal risk, and data quality. The data collected in this study will update the FDA pregnancy pharmacokinetic section for quetiapine and inform physicians that prescribe to childbearing women.

Bipolar Disorder (BD) and Schizophrenia (SCHZ) in pregnancy are associated with pregnancy complications and increased maternal mortality due to physiological and psychosocial changes independent of second-generation antipsychotic (SGA) use. Untreated BD and SCHZ have been associated with an increased risk of placental abnormalities, antepartum hemorrhage, preterm birth, pre-eclampsia, low birth-weight, intrauterine growth retardation, small for gestational age, fetal distress, neonatal hypoglycemia, stillbirth and congenital defects, and the potential for adverse neurodevelopmental outcomes. Severe maternal stress in pregnancy increases the risk for offspring mental disorders, and eye, ear, respiratory, digestive, skin, musculoskeletal, and genitourinary diseases and congenital malformations (i.e., cleft palate, cleft lip). Also, BD and SCHZ illness symptoms are linked to psychosocial consequences that result in poor perinatal outcomes including impulsivity that leads to reckless behavior such as increased indiscriminate sex and exposure to sexually transmitted infections, smoking, increased alcohol and drug use, less prenatal care, and poor nutrition. Furthermore, women with recurrence of mental illness in the perinatal period have increased risk for suicide, a leading cause of maternal death. The only published case of quetiapine plasma concentrations in a pregnant woman included cross-sectional levels of a woman on 300 mg of quetiapine across pregnancy and postpartum. Compared to six months postpartum, the area under the curve decreased by 27%, 42%, and 18% in the first, second, and third trimester, respectively. Given the complexity of the metabolism of quetiapine to a very active metabolite, it is important to understand the altered metabolism of quetiapine and its active metabolite in pregnancy and the implication for dosing adjustments. This study will investigate the longitudinal pharmacokinetics of quetiapine in pregnancy, delivery, and postpartum. The long-term goal of this line of research is to establish psychotropic medication dosing algorithms informed by longitudinal pharmacokinetic data to improve mental health and pregnancy outcomes for mothers with serious mental illness. The primary aims are: 1) Determine the elimination clearance of quetiapine and its major active metabolite, 7-N-desalkyquetiapine, across pregnancy and postpartum; 2) Determine the effect of pharmacokinetic changes on symptoms and toxicity during pregnancy and postpartum, and; 3) Examine the maternal-to-cord plasma concentrations ratios of quetiapine and its major active metabolite, 7-N-desalkylquetiapine.