Final answer:
Norvir is an important antiviral medication used in combination therapies to treat HIV by reducing the number of infectious virions and for treating hepatitis C virus (HCV) infections.
Step-by-step explanation:
Norvir is an antiviral drug used for the treatment of HIV infections, along with other antiretrovirals in a combination therapy. HIV, the retrovirus causing AIDS, can become resistant to treatment, making drug resistance a major challenge. Norvir can help reduce the number of infectious virions in the blood to non-detectable levels in many HIV-infected individuals by interfering with the virus's life cycle, specifically targeting viral enzymes crucial for replication. In addition, Norvir is used in treating hepatitis C virus (HCV) in combination with other drugs such as ribavirin and peginterferon alfa. It is noted for chemically resembling a normal RNA nucleoside, which allows it to be inserted into the viral RNA chain and inhibit further replication. The most successful use of antivirals like Norvir has been in the treatment of HIV, significantly prolonging the lives of those affected when compared to untreated individuals.