Antiviral
PREGNANCY RECOMMENDATION: Compatible—Maternal Benefit >> Embryo–Fetal Risk
BREASTFEEDING RECOMMENDATION: Contraindicated
PREGNANCY SUMMARY
No reports describing the use of valganciclovir in human pregnancy have been located. For ganciclovir, human pregnancy experience has not shown toxicity, but the number of cases is very limited. The animal data for ganciclovir are suggestive of high embryo–fetal risk because carcinogenic, mutagenic, teratogenic, and embryotoxic effects have been observed. Primary cytomegalovirus (CMV) infections occurring in pregnancy have a high risk of transplacental passage of the virus to the fetus. Some of the embryos or fetuses exposed to the virus will be damaged and the development of later toxicity in childhood is an additional concern. However, the prevention of these in utero infections by ganciclovir has not been proven (see Ganciclovir).
FETAL RISK SUMMARY
After oral administration, the prodrug valganciclovir is rapidly converted to ganciclovir by intestinal and hepatic enzymes. The antiviral effect, therefore, is identical to ganciclovir (see Ganciclovir). Valganciclovir is indicated for the treatment of CMV retinitis in patients with AIDS. Plasma protein binding of valganciclovir is not relevant because of its rapid metabolism to ganciclovir, but binding of ganciclovir is very low (1%–2%). The elimination half-life of ganciclovir after valganciclovir administration is about 4.1 hours, compared with 3.8 hours when IV ganciclovir is administered (1). Ganciclovir crosses the human placenta (see Ganciclovir).
Reproduction studies in animals have been conducted with the active metabolite ganciclovir (1) (see Ganciclovir).
BREASTFEEDING SUMMARY
No reports describing the use of valganciclovir during human lactation have been located. Because the active metabolite, ganciclovir, has the potential to cause serious toxicity in a nursing infant, mothers taking this drug should not breastfeed. Further, breastfeeding is contraindicated if the mother is infected with HIV.
Reference
1.Product information. Valcyte. Roche Pharmaceuticals, 2004.