Abstract
OBJECTIVE: The purpose of this study was to determine the valaciclovir and acyclovir pharmacokinetic profiles in serum and breast milk after valaciclovir administration to women after delivery. STUDY DESIGN: Valaciclovir (500 mg twice daily for 7 days) was given to 5 women after delivery who were breast-feeding healthy term infants. Matched serum and breast milk samples were obtained after the initial dose, on day 5 and 24 hours after the drug was discontinued. Infant urine was obtained on day 5. RESULTS: Valaciclovir was rapidly converted to acyclovir. The peak serum acyclovir concentration occurred 3 hours before the peak breast milk concentration (2.7 μg/mL at 1 hour vs 4.2 μg/mL at 4 hours). The serum acyclovir elimination half-life was 2.3 hours. The ratio of breast milk to serum acyclovir concentration was highest 4 hours after the initial dose at 3.4 and reached steady state ratio at 1.85. The median infant urine acyclovir concentration at steady state was 0.74 μg/mL. CONCLUSION: Valaciclovir is rapidly converted to acyclovir and concentrates in breast milk. However, the amount of acyclovir in breast milk after valaciclovir administration is considerably less (2%) than that used in therapeutic dosing of neonates.
Original language | English (US) |
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Pages (from-to) | 100-102 |
Number of pages | 3 |
Journal | American journal of obstetrics and gynecology |
Volume | 186 |
Issue number | 1 |
DOIs | |
State | Published - 2002 |
Keywords
- Acyclovir
- Breast milk
- Herpes simplex virus
- Valaciclovir
ASJC Scopus subject areas
- Obstetrics and Gynecology