Antiviral Agents Flashcards
Drugs against influenza?
- Amantadine
- Rimantadine
- Oseltamivir
- Zanamivir
- Peramivir
Amantadine & Rimantadine Mechanism of action?
inhibit viral uncoating by block of viral M2 proton chanel
Amantadine & Rimantadine Pharcokinetics?
Oral
accumulate in lung
Amantadine: Renal elimination
Rimantadin: Hepatic elimination
Amantadine & Rimantadine Spectrum/Use?
Treatment influenza A
Amantadine & Rimantadine Adverse Reactions?
- Amantadine:
* GI upset
* Insomnia
* Confusion headache - Rimantadine:
* better tolerated
* Poor CNS penetration
Oseltamivir, Zanamivir, Peramivir Mechanism of action?
inhibit viral neuraminidase to decrease viral budding (decrease infectivity)
Oseltamivir, Zanamivir, Peramivir Pharmacokinetics
All Renal excretion
Oseltamivir: oral as prodrug
Zanamivir: inhalation
Peramivir: IV
Oseltamivir, Zanamivir, Peramivir Spectrum
Treatment influenza A, B, C
Oseltamivir, Zanamivir, Peramivir Adverse reaction
oseltamivir: Nausea/ vomitting
Zanamivir: bronchospasm
Drugs against Herpes (HSV-VZV)/Cytomegalovirus (CMV)/ Respiratory Syncitial Virus (RSV)?
- Acyclovir (Valacyclovir)
- Penciclovir ( Famciclovir)
- Docosanol
- Ganciclovir
- Cidofovir
- Foscarnet
- Ribavirin
Acyclovir & Penciclovir Mechanism of Action (MoA)?
phosphorylated by viral thymidine kinase –> inhibits viral DNA polymerase & chain termination
Acyclovir Pharmacokinetics?
Topical, oral, IV
Acyclovir: 15-30% prodrugs
Valacyclovir: 80% prodrugs
Renal excretion
Penciclovir Pharmacokinetics?
Topical
Renal excretion
Famciclovir: 80% prodrugs
Acyclovir & Penciclovir spectrum?
HSV-1/HSV-2 : mucosal, genital, encehalitis
Varicella-zoster: higher dose
Acyclovir & Valacyclovir Adverse reaction (Adr)?
- Minor toxicity: headache, n/v
- Renal toxicity in IV route
- Valacyclovir: higher IV route –> CNS effect
Problem with higher levels valacyclovir?
increase risk CNS & renal side effects
Docosanol MoA?
inhibit fusion between plasma membrane and Herpes viral envelope
Docosanol Pharmacokinetic?
Topical (5x daily)
Docosanol Spectrum
HSV-1 labialis
Docosanol Adr?
well tolerated
Ganciclovir (Valganciclovir) MoA?
phosphorylated by viral thymidine kinase to active form that inhibits viral DNA polymerase
Ganciclovir (Valganciclovir) Pharmacokinetics?
Ganciclovir: Poor Oral
Valganciclovir: Good Oral
Distribute to CNS
Renal excretion
Ganciclovir (Valganciclovir) Spectrum?
Herpes (HSV-VZV)
Cytomegalovirus (CMV)
Ganciclovir comparing with Acyclovir?
More active, more toxic
Slight threatening CMV retinitis
Ganciclovir (Valganciclovir) Adr?
Bone marrow depression
CNS: HA, behavioral changes
Cidofovir MoA?
Nucleotide analog –> inhibit 2nd phosphorylation steps by host kinase–> inhibits viral DNA pol
Cidofovir Pharmacokinetics?
Long intracellular 1/2 life –> 17-35 hrs
How often giving cidofovir?
IV weekly/bi-weekly
Cidofovir Spectrum?
Against DNA virus
CMV infection
When to give Cidofovir for CMV infection?
If resistant to ganciclovir or foscarnet
Cidofovir Adr?
Nephrotoxicity = kidney toxic
Rash HIV patient
How to decrease nephortoxicity of cidofovir?
using concurrent with Probenecid
Foscarnet MoA?
- pyrophosphate analog –> NO activation step
2. inhibits “all” DNA/RNA pol and RT
Foscarnet Pharmacokinetics?
Poor oral
Continuous infusion!!
Foscarnet Spectrum?
CMV infection: if Ganciclovir resistant
Herpes infection: if acyclovir resistant
HIV: 2nd line
Foscarnet Adr?
Renal impairment
Severe n/v electrolyte imbalance (hypocalcemia)
Ribavirin MoA?
- triphosphorylated to active form
- inhibits IMP dehydrogenase
- inhibits viral RNA-dependent RNA pol
Ribavirin Pharmacokinetics
aerosol administration
Good Oral
Long intracellular 1/2 life
Ribavirin Spectrum
Respiratory syncital virus (RSV): inhalation
Hepatitis : oral (with interferon)
Ribavirin Adr?
Low aerosol toxicity
Systemic toxicity: anemia, bone marrow depression
Which Herpes drugs are eliminated by kidney? (3)
- Acyclovir
- Peniclovir
- Ganciclovir
Which type of analog is Ribavirin?
purine nucleoSIDE analog
- Whose kinase is responsible for phosphorylating ribavirin?
- What is the product?
- By cellular (host) kinasese
2. ribavirin-TP