August 30, 2010

Antiviral Drugs Safe During Pregnancy

(Ivanhoe Newswire) -- Mothers who are exposed to certain antiviral drugs during the first trimester of pregnancy do not face an increased risk of birth defects, according to a new study.

Researchers from Denmark conducted the study to determine if there was an association between the use of the antiviral drugs acyclovir, valacyclovir and famciclovir and major birth defects in women who used the treatments during their pregnancies. These drugs are often used to treat herpes simplex and herpes zoster infections.

Results showed among the 1,804 pregnancies exposed to acyclovir, valacyclovir or famciclovir at any time in the first trimester, 2.2 percent of infants had a major birth defect compared to 2.4 percent of infants who were not exposed to the drugs during pregnancy.

More than 1 percent of susceptible women acquire herpes simplex during the first trimester of pregnancy.

"Our study, to our knowledge the largest of its kind, found no significant association between first-trimester exposure to antiherpetic antiviral drugs and major birth defects," the authors concluded. "Consequently, it has immediate clinical implications and may support informed decisions on safety when prescribing antiviral for herpes infections in early pregnancy. Acyclovir is the most extensively documented antiviral and should therefore be the drug of choice in early pregnancy, while data on valacyclovir and famciclovir are still insufficient."   

SOURCE: JAMA, 2010;304:859-866