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-, IFN-β , INF- δ IFN-2b: widest application Pegilated- IFN-polyethyleneglycol 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-ribavirin Hepatitis B: INF-lamivudine (reverse

transcriptase inhibitor), adefovir, … Papillomavirus: Interferon- RSV: Ribavirin CMV:ganciclovir, foscarnet VZV: valacyclovir, famciclovir Picornavirus: pleconaril

Anti-influenza drugs

1. Influenza A: Amantadine Rimantadine2. 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