Antiviral agents

Viruses treatable with antiviral drugs HSV VZV CMV HIV Influenza A and B Respiratory syncytial virus (RSV) Hepatitis A, B, and C viruses (HAV;HBV;HCV) Papilloma Picornavirus

Agents active against Herpesviruses-I Acyclovir Cidofovir Famciclovir and penciclovir Foscarnet Fomivirsen

Agents active against Herpesviruses-II Ganciclovir Valacyclovir Valganciclovir Vidarabine Topical agents: -Trifluridine -Vidarabine

Revolution in the field of Infectious diseases: The availability of Increasing number of antiviral agents Against a broadening spectrum of viral pathogens

Mechanism of action of antiviral agents is essential , for appropriate clinical use and for understanding and managing antiviral resistance !

Acyclovir HSV encephalitis Neonatal HSV infection Primer genital HSV Mucosal and cutaneous HSV-1 and HSV-2 infections in immunocompromised patients VZV infection Recurrent genital herpes

Acyclovir resistance Mutation either in viral TK or DNA polymerase genes.

Cidofovir Broad activity: -adenoviruses -herpesviruses -papovaviruses -poxviruses

Cidofovir Prophylaxis and treatment of CMV retinitis in patients with AIDS Acyclovir and foscarnet resistent HSV infections

Famciclovir and Penciclovir DNA polimerase inhibitor Nucleoside analogue Famciclovir: synthetic Active metobolite: penciclovir 1% topical penciclovir

Famciclovir Singles (acute zoster) Genital HSV Mucocutaneous HSV in HIV infected patients

Foscarnet Pyrophosphate analogue DNA polymerase inhibitor RT inhibitor Active agains all herpesviruses, HIV, HBV

Foscarnet CMV retinitis in AIDS patients Acyclovir resistant mucuccutaneous HSV infections in AIDS patients Gancyclovir resistant CMV pulmoner infections in AIDS patients Acyclovir resistant VZV infections in AIDS patients

Fomivirsen Inhibits viral replication by antisense mechanism: its a nucleotide sequence which is complementary to a sequence in mRNA transkript and translation is inhibited. Intravitreal injection for CMV retinitis

Ganciclovir Guanoside analogue DNA polimerase inhibitor Similar to acyclovir i.v, oral and intraocular application

Ganciclovir Prevention and treatment of CMV retinitis in AIDS patients CMV disease in transplant patients

Valacyclovir Active metobolite= acyclovir

Vidarabine Nucleosid analogue First licensed systemic antiviral agent Acyclovir has supplanted vidarabine

Topical agents for HSV keratitis Trifluridine Vidarabine

Interferons Low molecular weight proteins With complex antiviral, immunomodulating, antiproliferative activities. Produced by eucaryotic cells in response to various inducers: viruses 3 types: IFN-a, IFN-β , INF- δ IFN-a2b: widest application Pegilated- IFN-a: + polyethylene glycol to the interferon, through a process known as pegylation, enhances the half-life of the interferon when compared to its native form.

HIV(Human immunodeficeincy virus) Nucleoside analogue reverse transcriptase inhibitors:Zidovudine (azidothymidine) Non- Nucleoside analogue reverse transcriptase inhibitors Protease inhibitors Fusion inhibitors Integrase inhibitors

Hepatitis C: Interferon-a, ribavirin Hepatitis B: INF-a, lamivudine (reverse transcriptase inhibitor), adefovir, … Papillomavirus: Interferon-a RSV: Ribavirin CMV:ganciclovir, foscarnet VZV: valacyclovir, famciclovir Picornavirus: pleconaril

Anti-influenza drugs Influenza A: Amantadine Rimantadine 2. Influenza A and B Zanamivir: enzyme inhibitors of neurominidase, virus release is inhibited. Oseltamavir: the same The length of disease is reduced if taken within the first 48hours