Not a tablet at all - this is acyclovir in a 5% topical cream, supplied in a tube without a house brand on the label.
Applied to the skin at the site of an outbreak, it acts locally on affected tissue instead of passing through the digestive tract and circulating around the body. That makes it a different tool from the oral Ekovir tablets that share the same active compound: a narrower reach, but no systemic load either.
Zovirax is the original trade name under which acyclovir was first sold; this is the generic equivalent of that cream.
