Antivirals

Question 1

What are viruses made of?

Answer 1

Protein coat (capsid)
nucleic acid core, genome
some have lipoprotein envelope

Question 2

What makes viruses antigenic?

Answer 2

the lipoprotein evelope

*viruses are obligate intracelluar parasites

Question 3

What are the two mechanisms antiviral agents need?

Answer 3

Either:

• block viral entry into or exit from the cell
• be active inside the host cell

to inhibit active replcation

Question 4

Do antiviral agents eliminate non-replicating or latent viruses?

Answer 4

No

• a virus has to be actively replicating for an antiviral drug to be effective.
• effective host immune response remains essential for the recovery from the viral infection

Question 5

What are the anti-HSV/VZV agents?

Answer 5

acyclovir (zovirax)
famcyclovir (famvir)
valacyclovir (valtrex)

• all guanine nucleoside analogs that inhibits viral DNA-polymerase
• only actively replicating viruses are inhibited

Question 6

What is the treatment of choice for HSV genital infections, orolabial, HSV encephalitis, HSV infection in immunocompromised and pregnant pts?

Answer 6

Acyclovir!

Question 7

Acyclovir

• distribution
• excretion
• routes of admin
• pregnancy/lactation

Answer 7

• all body tissues and CNS
• renal excretion
• Topical, oral, IV
• Category B pregnancy, safe for lactation

Question 8

How does acyclovir selectively destroy cells?

Answer 8

It is a prodrug that enters all cell and only becomes activated in herpes infected cells by phosphorylation. Uninfected cells do not phosphorylate acyclovir.

Question 9

Acyclovir

-adverse effects

Answer 9

• GI sx
• HA
• rash
• photosensitivity
• anemia
• reversible renal toxicity (crystallization in the renal tubules)
• Neuro sx (somnolence, hallucinations, coma, confusion)
• TTP/HUS

Question 10

Famciclovir

• routes of administration
• metabolism
• excretion
• pregnancy/lactation
• mechanism

Answer 10

• orally only
• first pass metabolism in intestine and live results in conversion to pencyclovir
• renal excretion
• Pregnancy cat B, lactation: safety unknown
• mechanism is similar to acyclovir (taken up in an infected cell and phosphorylated to the active form)

Question 11

Famcyclovir

-adverse effects

Answer 11

• GI sx
• HA
• Fatigue
• abnormal LFTs
• neutropenia
• thrombocytopenia
• neuro sx (somnolence, hallucinations, delirium)

Question 12

Valacyclovir

• Mechanism
• exceretion
• routes of admin
• advantage
• disadvantage
• preg/ lactation

Answer 12

• It is a prodrug of acyclovir, undergoes rapid first pass metabolism to yeild acyclovir
• renal excretion (>50%)
• Oral, food does not affect absoption
• better oral bioavailbility, more conveinent dosing
• more pricey
• Pregnancy cat B, lactation: safe

Question 13

Valcyclovir

-Adverse effects

Answer 13

• GI sx
• HA
• rash
• photosensitivity
• elevated LFTs
• Reversible renal toxicity
• neuro sx
• TTP/HUS

Question 14

What is the drug of choice for HSV Keratoconjunctivitis?

Answer 14

Trifluridine (Viroptic)

-dendritic lesion in eye

Question 15

What is the drug of choice for CMV retinitis in immunocompromised patients and prevention of CMV disease in transplant patients?

Answer 15

Ganciclovir (Cytovene)

Question 16

Ganciclovir

• routes of admin
• excretion
• pregnancy/ lactation
• adverse effects

Answer 16

• Oral, IV, intraocular
• renal (>90%, unchanged)
• Preg cat C, lactation: unsafe

AE
-reversible pancytopenia
-fever
rash
-phlebitis
-confusion
-renal dysfunction
-psych disturbances
-seizures

Question 17

What is essential for the replication of the influenza virus?

Answer 17

enzyme neuraminidase is essential for replication

Question 18

What are the neurominidase inhibitors and how do they work?

Answer 18

Oseltamivir
Zanamavir

-prevent the release of new virons and their spread from cell to cell

can be used for both prophylaxis and acute treatment

Question 19

Zanamivir

• routes of admin
• adverse effects

Answer 19

• inhalation

- nasal and throat discomfort, bronchospasm

Question 20

Amantadine and Rimantadine
Adverse effects
Why are they not currently recommended in the US?

Answer 20

• Seizures
• anticholinergic
• CNS
• edema
• blurry vision

-too much resistance!

Question 21

Ribavirin is the drug of choice for?

alternative for?

Answer 21

-RSV bronchiolitis and pneumonia in hospitalized children, lassa fever

alternative for: influenza, para influenza, measles, HCV

Question 22

Ribavirin
routes of admin
preg/ lacation
adverse effects

Answer 22

• Orally and inhalation (IV from CDC)
• Preg cat X, latation: probably unsafe

AE

• BBW- hemolytic anemia
• resp deterioration
• depression
• suicidal ideation
• psych issues
• anxiety
• fatigue
• dizziness

Question 23

How do you get:
Hep A
Hep B
Hep C

Answer 23

A: oral-fecal route, clears on its own

B: sex, needles, may clear on its own (may be chronic)

C: most likely to cause permanent damage. same stuff

Question 24

Standard treatment for Hep C?

SE?

Answer 24

Ribavarin plus interferon

SE:
severe flu like sx
fatigue 
depression
anemia

Question 25

What are the drugs of choice for HBV and HCV?

Answer 25

Ribavirin
Interferons
lamivudine
entecavir
sofobuvir (sovaldi)
simeprivir (olysio)
ledipasvir-sofobuvir (Harvoni)