This document discusses antiviral drugs, including their mechanisms of action, clinical uses, and drugs used to treat various viruses. It classifies antiviral agents according to how they work and describes ideal antiviral agents. It then discusses specific antiviral drugs for influenza, herpes simplex virus, herpes zoster virus, cytomegalovirus, hepatitis B, and hepatitis C. The document provides details on antiviral drugs for different viruses, their advantages and disadvantages, dosing, and resistance. It also covers interferons and their use as antiviral and immunostimulating agents.

1. Antiviral drugs

2. Learning objectives
By the end of the lecture
1. Classify antiviral agents according to the
mechanism of action
2. Describe the clinical uses, ADRs
3. Enumerate the drugs used in management of
influenza, HSV,HZV, HBV,HCV

3. Introduction
• Smallest infective agents
• Intracellular parasite
• Cannot replicate
• Survival outside host cell
• Replication -maximum
• Difficult to kill

8. Anti-viral drugs

9. Ideal anti-viral agents
• Greater selectivity
• Low toxicity to host
• Invivo stability
• Kill latent viruses

14. Influenza A
• Affects various species
• Pandemic
• H1N1, H1N2, H3N2
• H5N1

15. • Primary target – M2 protein ion channel
• Resistance – mutation in M2 protein

17. • s/e – GI intolerance, dizziness,
lightheadedness,insomnia
• CI – ulcer, epilepsy, pregnancy
• Rimantidine – 4- 10 times more active
• less neurotoxic, more GI intolerance

21. • Resistance – mutation on viral TK, viral DNA
polymerase
• Cross resistance - ganciclovir, famciclovir

24. • HSV …. 400mg BD-8-10days
• 5% oinment
• Parentral – meningitis, encephalitis

25. • Varicella – reduces cutaneous and visceral spread
used within 24 hrs
800mg BD, oral,IV
• HZ- reactivation – 800mg 5 times/day, 5%
oinment
• Prophylactic use – immuosupressants –prevent
reactivation

26. • A/E – continous IV infusion – crystalline
nephropathy
• Reversible neurotoxicity – tremor, delirium ,
disorientation

28. • Advantage- more efficacy
• CMV prevention
• Reduces pain duration in HZ
• Reduce frequency of post herpetic neuralgias
Dis adv- TTP in high dose, HUS

29. • Famciclovir
• Prodrug of penciclovir
• Good oral BA
• Alternative to acyclovir
– HSV, VZV
• Reduce duration of
postherpetic neuralgia
• Pencilovir
• Active metabolite of
famciclovir
• 1% cream – herpes
labialis
• T1/2 -8-20hrs

34. cidofovir
• T1/2- 2-3 hrs / metabolite , once a week
• Peak conc higher with probenecid
• Reduce nephrotoxicity

39. Fomivirsen
• It is a oligonucleotide –acts by anti-sense
mechanism
• Intravitreally – CMV in AIDS
• Resistance – not reported

41. Ribavirin
• Inhibits viral mRNA, viral RNA polymerase
• Broad pectrum
• Infu A,B, HCV, RSV, HIV-1
• Inhalation,oral
• With peginterferon alpha – HCV
• A/E- hemolytic anemia, insomnia, fatigue

44. • Inhibits release of progeny virus
• Inhibits spread of infection with in respiratory
passage
• Resistance – mutation in neuroaminidase
enzyme
• Prophylaxis for high risk

47. Interferons

48. • Endogenous substance – glycoprotein
• Inhibit viral translation
• Species specific Not disease specific
• Immunostimulant, antiprol, antiviral
• Types - alpha, beta, gamma

49. • ROA- SC/IM
• Peg IFN –recombinant
• Prolongs the DOA

58. HCV
• Grouped according to target NonStructural
protein
• NS5A inhibitor-Daclatasvir, Ledipasvir,
velpatasvir, Elbasvir, ombitasvir
• NS5B polymerase inhibitor –Sofosbuvir,
Dasabuvir
• NS3/4A protease inhibitor – simeprevir,
grazoprevir, paritaprevir

61. Summary
• Intracellular parasite
• Replication
• Classification
• HZV, HSV, CMV,
• Influenza
• HBV/ HCV

62. Thank you..

63. Questions
• Drug of choice for CMV
• DOC for acyclovir resistant VZV
•
• Drug must be phosphorylated by viral TK
• Drug that do not require phosphorylation

64. • DOC for viral encephalitis
• Via inhalation
• Nephrotoxicity