Take acyclovir with food or milk to lessen stomach upset. Acyclovir is an antiviral drug. It does not cure the infection, but it slows the growth and spread of the virus so that your body can fight off the infection. Acyclovir lessens the symptoms of these infections and shortens the length of time you are sick. Acyclovir is used to treat infections caused by herpes viruses.
Illnesses caused by herpes viruses include genital herpes, cold sores, shingles, and chicken pox.
Acyclovir may also be used for purposes other than those listed in this medication guide. Before taking this medication, tell your doctor if you have any type of kidney disease. You may need a lower dose or special monitoring during therapy with acyclovir. This means that it is not known whether acyclovir will harm an unborn baby. Do not take this medication without first talking to your doctor if you are pregnant.