Valtrex for Herpes OK While Breastfeeding

Feb. 11, 2002 -- Is it safe to treat genital herpes when I'm breastfeeding? That question pops up all the time on the WebMD Genital Herpes message board. And now a new study shows that one commonly used drug, Valtrex, appears to be safe for your child.

"I have [genital herpes] and my OB has put me on Valtrex for the last four weeks of my pregnancy. I am concerned about breastfeeding. First of all, the Valtrex precautions advise not to breastfeed during the use of medication. Please help!" says one WebMD Member.

Genital herpes, caused by the herpes simplex virus, is very common in the U.S. Currently, about one in every five people has the disease and this number continues to grow, according to the study researchers.

There is no cure for genital herpes. Once someone is infected, the virus lives in the body forever. There are very effective medicines, however, that can treat an outbreak. These medicines can also help keep the virus from reactivating in people who have frequent, repeated outbreaks.

Acyclovir was the first drug used for genital herpes. But in recent years, Valtrex and Famvir have made treatment much easier. Valtrex is changed to acyclovir in the intestines but the benefit is that it stays around much longer -- allowing people to take it twice a day instead of five times a day.

But what about during breastfeeding? Is it safe for the baby?

Doctors already know that acyclovir does cross into breast milk -- at levels that don't seem to be harmful to infants. But since Valtrex is a much more active drug, researchers at the University of Texas Southwestern Medical Center in Dallas wanted to see if this drug was also safe.

Lead author Jeanne S. Sheffield, MD, and colleagues gave Valtrex -- 500 mg twice a day for seven days -- to five women who were breastfeeding. The amount of Valtrex and acyclovir (remember that Valtrex is changed to acyclovir in the body) in breast milk was tested while on the drug. The amount of the drug in the infant's urine was also tested.

Acyclovir was found in the breast milk. However, the amount seen in the milk was considerably less than that used to treat infants that have been infected with herpes. No Valtrex was found in the milk.

Four studies have shown that acyclovir does accumulate in breast milk but they also showed that there were no problems seen in the infants. The American Academy of Pediatrics considers acyclovir to be safe during breastfeeding, according to the researchers.

And the current study, the researchers say, confirms that Valtrex is not found in breast milk. They conclude that Valtrex is safe during breastfeeding.

This information should come as a relief to women and their doctors. But before deciding to take Valtrex while breastfeeding, be sure to check with your doctor. This study suggests that it would be safe for your baby, but you and your doctor still need to make this decision together.