valacyclovir and Hepatitis-C

Most viral diseases, with the exception of those caused by human immunodeficiency virus, are self-limited illnesses that do not require specific antiviral therapy. The currently available antiviral drugs target 3 main groups of viruses: herpes, hepatitis, and influenza viruses. With the exception of the antisense molecule fomivirsen, all antiherpes drugs inhibit viral replication by serving as competitive substrates for viral DNA polymerase. Drugs for the treatment of influenza inhibit the ion channel M(2) protein or the enzyme neuraminidase. Combination therapy with Interferon-α and ribavirin remains the backbone treatment for chronic hepatitis C; the addition of serine protease inhibitors improves the treatment outcome of patients infected with hepatitis C virus genotype 1. Chronic hepatitis B can be treated with interferon or a combination of nucleos(t)ide analogues. Notably, almost all the nucleos(t) ide analogues for the treatment of chronic hepatitis B possess anti-human immunodeficiency virus properties, and they inhibit replication of hepatitis B virus by serving as competitive substrates for its DNA polymerase. Some antiviral drugs possess multiple potential clinical applications, such as ribavirin for the treatment of chronic hepatitis C and respiratory syncytial virus and cidofovir for the treatment of cytomegalovirus and other DNA viruses. Drug resistance is an emerging threat to the clinical utility of antiviral drugs. The major mechanisms for drug resistance are mutations in the viral DNA polymerase gene or in genes that encode for the viral kinases required for the activation of certain drugs such as acyclovir and ganciclovir. Widespread antiviral resistance has limited the clinical utility of M(2) inhibitors for the prevention and treatment of influenza infections. This article provides an overview of clinically available antiviral drugs for the primary care physician, with a special focus on pharmacology, clinical uses, and adverse effects.

Topics: Acyclovir; Adenine; Amantadine; Antiviral Agents; Comorbidity; Drug Therapy, Combination; Foscarnet; Ganciclovir; Guanine; Hepatitis; Hepatitis B, Chronic; Hepatitis C; Herpesviridae Infections; HIV Infections; Humans; Influenza, Human; Interferons; Lamivudine; Nucleosides; Oligopeptides; Organophosphonates; Oseltamivir; Proline; Protease Inhibitors; Pyrimidinones; Ribavirin; Telbivudine; Thymidine; Valacyclovir; Valganciclovir; Valine; Virus Replication; Zanamivir

The current arsenal of antiviral agents available to the practitioner is expanding rapidly, such that by the time this article goes to press, new drugs may have already been added. Although the majority of approved drugs have been developed for use in only a few viral infections (eg, HIV, herpesviruses, and papillomavirus), discoveries made in the development of these drugs may lead to antiviral agents effective against other viruses. In addition, new uses for the currently available drugs are under evaluation. This review of antiviral agents discusses the treatments available for viral infections such as herpes simplex virus, varicella zoster virus, cytomegalovirus, human papillomavirus, chronic viral hepatitis, and others.

Topics: 2-Aminopurine; Acyclovir; Antiviral Agents; Chickenpox; Cytomegalovirus Infections; Famciclovir; Foscarnet; Guanine; Hepatitis B; Hepatitis C; Herpes Genitalis; Herpes Simplex; Herpesvirus 3, Human; Herpesvirus 8, Human; Humans; Papillomavirus Infections; Sarcoma, Kaposi; Skin Diseases, Viral; Valacyclovir; Valine

Topics: 2-Aminopurine; Acyclovir; Antiviral Agents; Cytomegalovirus Infections; Drug Resistance, Viral; Famciclovir; Guanine; Hepatitis B; Hepatitis C; Herpes Simplex; Herpes Zoster; Humans; Influenza, Human; Valacyclovir; Valine; Virus Diseases