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Updated: Jun 26, 2026
09:04
Comprehensive Evaluation of the Effectiveness and Safety of Placenta-Targeted Drug Delivery Using Three Complementary Methods
Published on: September 10, 2018
Clonidine pharmacokinetics in pregnancy
M L Buchanan1, T R Easterling, D B Carr
1Department of Pharmacy, University of Washington, 1959 NE Pacific Street, H-375 Health Sciences Center, Box 357630, Seattle, WA 98195-7630, USA.
Summary
Pregnant women clear clonidine (a medication) significantly faster than nonpregnant individuals. Fetal exposure to clonidine at birth mirrors maternal plasma levels, indicating efficient placental transfer.
Area of Science:
- Pharmacology
- Obstetrics
- Maternal-Fetal Medicine
Background:
- Clonidine is used to treat hypertension, but its pharmacokinetics during pregnancy are not well-established.
- Understanding drug disposition in pregnancy is crucial for safe and effective maternal care.
Purpose of the Study:
- To determine the pharmacokinetic parameters of clonidine in pregnant women.
- To compare these parameters with previously published data in nonpregnant subjects.
- To assess fetal exposure to clonidine at the time of delivery.
Main Methods:
- Serial blood and urine samples were collected from 17 pregnant women.
- Noncompartmental pharmacokinetic parameters and creatinine clearance were calculated.
- Maternal and umbilical cord plasma samples were analyzed for clonidine concentrations at delivery.
Main Results:
- Clonidine apparent oral clearance was significantly higher in pregnant women (440 ml/min) compared to nonpregnant subjects (245 ml/min).
- A strong correlation was observed between clonidine renal clearance and urine pH.
- Umbilical cord to maternal plasma clonidine concentration ratios were approximately 1.0 for both arterial and venous samples.
Conclusions:
- Clonidine is cleared more rapidly in pregnant women than in nonpregnant individuals.
- The fetus is exposed to similar plasma clonidine concentrations as the mother at the time of delivery.
- These findings have implications for clonidine dosing and monitoring during pregnancy.
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