Herpes is a viral disease caused by one of the two existing herpes simplex viruses: HSV-1 and HSV-2. Herpes drugs used against this condition act by interfering with the replication of the virus, slowing it and giving the immune system a chance to eliminate the disease. Antiviral medications include acyclovir (Zovirax- best option in the last months of pregnancy in order to stop the transmission of the virus), famciclovir (Famvir), valaciclovir (Valtrex) and penciclovir. Other drugs such as Cimetidine (commonly used for heartburn) might be useful, also low dose aspirin (for recurrent cases) and there are also vaccines, like Zostavax.