an oral antiviral drug (trade name Zovirax) used to treat genital herpes; does not cure the disease but relieves the symptoms
"After my doctor confirmed I had a recurrent outbreak of genital herpes, she prescribed acyclovir to help shorten the duration and reduce the painful sores."
US and Britain spelling of aciclovir.
"The doctor prescribed acyclovir for my cold sore infection, which is just the American spelling of aciclovir."