Relationships between endogenous CYP3A markers and plasma amlodipine exposure and metabolism in early postpartum and non-peripartum women with hypertension.

ABSTRACT

OBJECTIVE: This study aimed to evaluate the relationship between endogenous CYP3A markers and plasma amlodipine (AML) exposure and metabolism parameters in early postpartum and non-peripartum women. METHODS: Twenty-four AML-treated early postpartum women with hypertensive disorders of pregnancy and 30 non-peripartum women with essential hypertension were enrolled. Blood samples for determination of CYP3A markers including total cholesterol-adjusted 4ß-hydroxycholesterol (4ß-OHC/TC), 25-hydroxyvitamin D (25-OHD), and AML and its metabolites in plasma were collected at 24 h after the AML treatment. RESULTS: The plasma 4ß-OHC/TC in postpartum women was higher than that in non-peripartum women, while the plasma 25-OHD was lower. The postpartum women had a lower plasma AML concentration and its metabolic ratio was higher. The plasma 4ß-OHC/TC decreased as the number of days post-delivery increased. The plasma AML concentration increased as the number of days post-delivery increased, while the metabolic ratio of AML declined slightly. Tendency toward negative correlations between the plasma 4ß-OHC/TC but not 25-OHD, and AML concentration were observed in both postpartum and non-peripartum women. In both groups, the plasma 4ß-OHC/TC was correlated with the metabolic ratio of AML. CONCLUSIONS: The early postpartum women had higher plasma 4ß-OHC and AML metabolism. The plasma 4ß-OHC had positive relationships with amlodipine metabolism in both women groups. AML metabolism and plasma 4ß-OHC may be useful as CYP3A markers in early postpartum and non-peripartum women.