What is Zovirax?
Zovirax is intended for local and systemic application in patients with following diseases:
- infectious diseases of skin and mucous membranes caused by herpes virus of I and II types;
- primary genital herpes and its recurrence;
- infectious diseases caused by chicken pox virus and herpes zoster;
- herpetic infection of I and II types at newborns;
- this medicine is also applied for prevention of the infectious diseases caused by simple herpes virus in patients suffering from immunodeficiency;
- for prevention of a cytomegaloviral infection at operations on bone marrow transplant.
Zovirax is also applied for treatment of the keratitis of virus etiology (in particular simple herpes provoked by a virus).
It's a virostatic drug containing active ingredient Acyclovir. This is a synthetic substance with a structure similar to guanine (a component of nucleinic acids complementary to cytosine), at interaction with specific enzymes Acyclovir transforms into pharmacological active agent. In the cells infected with viruses a specific enzyme called thymidinekinase is produced. It transforms the remedy into Acyclovir triphosphate. Saturation of cytoplasm of the infected cell with triphosphate interferes with replication of virus DNA which prevents normal reproduction of viruses and formation of inviable virus units. The mechanism of remedy action is based on its structural similarity to deoxyguanosine triphosphate which accounts for a competitive replacement of nucleotide with an Acyclovir triphosphate during the synthesis of virus DNA. The medicine doesn't influence healthy cells of an organism as there is no enzyme of thymidinekinase and the drug remains in its inactive form. Besides, concentration of the drug in infected cells is much higher, than in healthy ones. The medicine shows virostatic activity concerning simple herpes virus of I and II type causing chicken pox. Zovirax is moderately active concerning cytomegaloviruses.
At prolonged use of the drug, especially in patients suffering from immunodeficiency, viruses develop resistance to the medicines containing Acyclovir. Resistant strains of viruses are characterized by low content or structure violation of thymidinekinase, changes in structure of virus DNA polymerase.
At use of the medicine in the form of eye ointment the drug is quickly absorbed through cornea and creates high concentrations in intraocular liquid. Systemic absorption of the drug is insignificant, Zovirax is practically not found in blood plasma, small quantity of the remedy is detected only in urine.
At use of the remedy in the form of ointment, systemic absorption of Zovirax is insignificant and doesn’t influence chemical composition of blood.