Zovirax tablets treat infections with herpes viruses

Zovirax tablets contain the active ingredient aciclovir, which is an antiviral medicine used to treat infections with herpes viruses. The herpes viruses include the viruses that cause cold sores and genital herpes (herpes simplex 1 and 2) and the virus that causes chickenpox and shingles (varicella zoster or herpes varicellae). Aciclovir works by stopping these herpes viruses from reproducing and infecting more cells in the body.

Aciclovir is converted to a more active form inside cells of the body that are infected with herpes viruses. The activated aciclovir then works by blocking the action of a viral enzyme called DNA polymerase.

The herpes viruses need the DNA polymerase enzyme to copy their genetic material from RNA to DNA. This process is necessary for the viruses to multiply and continue to survive. By blocking the action of DNA polymerase, aciclovir prevents the herpes viruses from multiplying. This controls the infection and helps the immune system to deal with it.

Studies in patients with frequent genital herpes recurrences (6 or more episodes per year) have shown that orally administered Zovirax given daily for 4 months to 10 years prevented or reduced the frequency and/or severity of recurrences in greater than 95% of patients.

In a study of patients who received Zovirax 400 mg twice daily for 3 years, 45%, 52%, and 63% of patients remained free of recurrences in the first, second, and third years, respectively. Serial analyses of the 3-month recurrence rates for the patients showed that 71% to 87% were recurrence free in each quarter.