Generic name : acyclovir (oral) [ a-SYE-klo-veer ] Brand names: Zovirax, Sitavig Dosage forms: buccal tablet (50 mg), oral capsule (200 mg), oral tablet (400 mg; 800 mg), oral suspension (200 mg/5 mL) Drug class: Purine nucleosides What is Acyclovir? Acyclovir (also called Zoviraxa) is a medicine that is commonly used to treat viral infections. It belongs to a class of drugs known as antivirals. Acyclovir works by slowing down the growth and spread of the herpes simplex virus which causes conditions like cold sores, genital herpes and shingles. In this article, we will explore what is Acyclovir, its side effects, what to do if you miss a dose or overdose, special instructions for taking Acyclovir and answer some popular frequently asked questions. Acyclovir is available in the following forms: 200 mg tablets taken by mouth 400 mg and 800 mg capsules taken by mouth A white 40 mg/mL liquid taken by mouth A clear liquid is given into a vein (IV) A cream that is applied to the skin Wh