Zovirax is an antiviral cream used to treat genital herpes, as well as cold sores on the face or lips. Zovirax does not cure cold sores or genital herpes, but merely stops the herpes simplex virus from replicating and causing bigger or longer lasting sores. The main active ingredient in Zovirax is acyclovir.
Description
Acyclovir is a white powder with a chemical name of 2-amino-1,9-dihydro-9-[(2-hydroxyethoxy)methyl]-6H-purin-6-one. It is a synthetic nucleoside analogue with antiviral properties. Acyclovir is considered a category B drug, which means that while acyclovir does not cause birth defects in animals, not enough human clinical studies have been completed to deem acyclovir safe to use in pregnant women. Thus, acyclovir should only be used by pregnant women when the benefits clearly outweigh the risks.
Mechanism
Acyclovir has antiviral properties against herpes simplex virus 1 and herpes simplex virus 2, as well as varicella-zoster virus. The HSV and VZV viruses make an enzyme called thymidine kinase that is highly selective for acyclovir. The TK enzyme converts acyclovir into acyclovir monophosphate. Another enzyme, cellular guanylate kinase, converts acyclovir monophosphate into acyclovir diphosphate. Numerous cellular enzymes then convert acyclovir diphosphate into acyclovir triphosphate. In vitro, that is in test tube studies, acyclovir triphosphate inhibits herpes viral DNA replication. Acyclovir triphosphate inhibits viral DNA polymerase, the enzyme that helps make new DNA, and attaches to and terminates the viral DNA chain being made.
Side Effects
Acyclovir has common side effects of dry or cracked lips if used for cold sores, flaky and dry skin, burning or stinging skin, and redness or irritation at site of application. Less common and more dangerous side effects indicating allergic reaction include rash, hives, itching, hoarseness, difficulty breathing, difficulty swallowing, and swelling of the face, lips, eyes, hands, feet, ankles, or legs.
Member Comments