It comes as a tablet, capsule, and liquid suspension. Depending on your condition, you might need to take it by mouth 2 to 5 times a day. Acyclovir works best when you start it as soon as symptoms begin. Common side effects include nausea, vomiting, and diarrhea. Intravenous aciclovir is effective in treating severe medical conditions caused by different species of the herpes virus family, including severe localized infections of the herpes virus, severe genital herpes, chickenpox and herpesviral encephalitis. Acyclovir is used to treat viral infections like chickenpox, herpes zoster (shingles) and genital herpes (a sexually transmitted disease). Acyclovir is in a class of medications called antivirals. It works by stopping the spread of the virus in the body. Zovirax is used to treat infections caused by herpes viruses, such as genital herpes, cold sores, shingles, and chickenpox. Zovirax will not cure herpes, but it can lessen the symptoms of the infection. Although acyclovir will not cure shingles or genital herpes, it does help relieve the pain and discomfort and helps the sores heal faster. This medicine is available only with your doctor's prescription. This product is available in the following dosage forms: Medscape - Herpes simplex, zoster-specific dosing for Zovirax (acyclovir), frequency-based adverse effects, comprehensive interactions, contraindications, pregnancy & lactation schedules, and. NHS information about aciclovir, including what it's used for, who can use it, how to use it and side effects. The acyclovir oral tablet is used to treat viral infections like shingles, genital herpes, and chickenpox. This form is available as both a generic drug and the brand-name drug Zovirax. Acyclovir is an antiviral drug. It slows the growth and spread of the herpes virus in the body. Acyclovir will not cure herpes, but it can lessen the symptoms of the infection. Acyclovir is used to treat infections caused by herpes viruses, such as genital herpes, cold sores, shingles, and chicken pox. Find patient medical information for Acyclovir (Zovirax) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings.