Valacyclovir

The Basics

What is Valacyclovir?

Used to treat shingles and genital herpes.

Brand names for Valacyclovir

Valtrex

How Valacyclovir is classified

Anti-Infective Agents, Antiviral Agents

Valacyclovir During Pregnancy

Valacyclovir pregnancy category

Category BNote that the FDA has deprecated the use of pregnancy categories, so for some medications, this information isn’t available. We still think it’s useful to list historical info, however, given what a common proxy this has been in the past.

What we know about taking Valacyclovir while pregnant

Clinical data over several decades with valacyclovir and its metabolite, acyclovir, in pregnant women, have not identified a drug associated risk of major birth defects. There are insufficient data on the use of valacyclovir regarding miscarriage or adverse maternal or fetal outcomes (see Data). There are risks to the fetus associated with untreated herpes simplex during pregnancy (see Clinical Considerations). In animal reproduction studies, no evidence of adverse developmental outcomes was observed with valacyclovir when administered to pregnant rats and rabbits at system exposures (AUC) 4 (rats) and 7 (rabbits) times the human exposure at the maximum recommended human dose (MRHD) (see Data). The estimated background risk of major birth defects and miscarriage for the indicated populations is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

Taking Valacyclovir While Breastfeeding

What are recommendations for lactation if you're taking Valacyclovir?

The dosage of acyclovir in milk after valacyclovir is less than 1% of a typical infant dosage and would not be expected to cause any adverse effects in breastfed infants. No special precautions are required when using valacyclovir during breastfeeding. In one study, administration of valacyclovir to mothers with concurrent herpes simplex type 2 and HIV infections reduced breastmilk shedding of the HIV virus in breastmilk at 6 and 14 weeks postpartum, but not later.[1] In another study in HIV-positive mothers, valacyclovir did not reduced breastmilk shedding of cytomegalovirus (CMV) or infant CMV acquisition.[2]

Maternal / infant drug levels

The dosage of acyclovir in milk after valacyclovir is less than 1% of a typical infant dosage and would not be expected to cause any adverse effects in breastfed infants. No special precautions are required when using valacyclovir during breastfeeding. In one study, administration of valacyclovir to mothers with concurrent herpes simplex type 2 and HIV infections reduced breastmilk shedding of the HIV virus in breastmilk at 6 and 14 weeks postpartum, but not later.[1] In another study in HIV-positive mothers, valacyclovir did not reduced breastmilk shedding of cytomegalovirus (CMV) or infant CMV acquisition.[2]

Possible effects of Valacyclovir on milk supply

Relevant published information was not found as of the revision date.

Possible alternatives to Valacyclovir

Acyclovir.