Systemic AntiVirals PDF

Viruses: obligate intracellular parasites/structure Capsid: cell membrane that is necessary to attach ○ Nuclear capsid: covering that has DNA material and how it is protected ○ Herpes zoster is DNA virus and do not reverse transcriptase vs. COVID virus is...

Viruses: obligate intracellular parasites/structure Capsid: cell membrane that is necessary to attach ○ Nuclear capsid: covering that has DNA material and how it is protected ○ Herpes zoster is DNA virus and do not reverse transcriptase vs. COVID virus is a RNA virus Viral Process Attachment and penetration of host cell → Synthesis of early viable nonstructural viral protein → Replication of viral genome → Synthesis of late structural proteins → Assembly of viral particles and their release from host cell Difficulties in generating effective treatment of antiviral drugs Lack of specificity ○ In order to kill a virus, you have to get into its genome and some drugs cannot do that ○ In order to be truly effective, you have to get into its genome Intracellular replication Asymptomatic incubation Escape of immune surveillance Latent/dormant stage ○ Herpes simplex → Chickenpox ○ Herpes Zoster → Shingles is secondary to Herpes Zoster  ○ Mutation/drug resistance Respiratory Virus Infection Orthomyxovirus ○ Influenza A and B and C Type A (more virulent and contagious): Potentially severe illness, rapidly changing, epidemics and pandemics Type B: usually less severe illness, epidemics, more uniform Type C: usually mild or asymptomatic illness, minimal public health impact Tx: preferred treatment is prevention with vaccines Oseltamivir (Tamiflu)/Zanamivir (Relenza- oral inhaler) ○ Neuraminidase inhibitors: prevent the release of new virions ○ Oseltamivir: ester prodrug converted to oseltamivir carboxylate 75 mg BID x 5 days Administered in 1st 24-48 hrs of symptoms Metabolism: liver, ½ life = 6-10 hrs Excretion: primarily urinary,