Antivirals - Smith 2017

Question 1

Antigens on new viruses that are slightly mutated to prevent host immune system from recognizing the virus is called what?

Answer 1

Antigenic drift

*Larger changes that may result in viral epidemics are antigenic shifts

Question 2

Acyclovir, Valcyclovir, Famcyclovir, Penicyclovir, Ganciclovir and Foscarnet are antiviral drugs that act on what?

Answer 2

Inhibit DNA polymerase

Question 3

Amantadine is an antiviral drug that does what?

Answer 3

Inhibits viral uncoating (M2 Protein)

Question 4

Ribavarin is an antiviral drug that does what?

Answer 4

Inhibits viral translation by inhibit RNA polymerase

Question 5

Zanamivir and oseltamivir are antiviral drugs that do what?

Answer 5

Inhibit neuroaminidase (viral release)

Question 6

What are the two categories of Herpes simplex virus? Where does each manifest typically? What ganglia does each reside in typically?

Answer 6

HSV Type 1 (Oral herpes, resides in trigeminal ganglia)

HSV Type 2 (Genital herpes, resides in sacral ganglia)

Question 7

What are the two main diseases caused by VZV?

Answer 7

1-Chickenpox (Varicella initial infection)

2-Shingles (herpes zoster reactivation)

Question 8

In general, canker sores are found ______ the mouth while Cold sores (fever blisters) are found _______ the mouth. Which is contagious?

Answer 8

Inside, outside

cold sores are contagious.

Question 9

What are the 4 main drugs used for Antiviral treatment of HSV and VZV?

Answer 9

1-Acyclovir (mainly HSV, 10x more potent against HSV than VZV)
2-Valacyclovir (converts to acyclovir via first pass metabolism)
3-Famiciclovir (metabolized to penciclovir, primarily used for VZV)
4 - penicyclovir

*Must hydrate well on these drugs to avoid crystalline nephropathy

Question 10

Which antiviral is used topically for orofacial or genital HSV related sores? and is topical only

Answer 10

Penciclovir

Question 11

Which antiviral is approved for prophylaxis and treament of cytomegalovirus? What is the contraindication for this drug? What is the route of administration for this drug because of its risk for cytotoxicity?

Answer 11

Gancyclovir

*contraindicated in pregnant or males who wish to bear children

Question 12

Which antiviral is used for CMV in immunocompromised patients and is useful when acyclovir or ganciclovir resistant? it is also safer than Gancyclovir. What is its worst side effect?

Answer 12

Foscarnet

worst side effect is nephrotoxicity

Question 13

What viral enzyme is necessary to activate acyclovir and allow it to incorporate into viral DNA, thus blocking its ability to elongate?

Answer 13

Viral Thymidine kinase

*acyclovir monophosphate lacks 3’ hydroxyl group and cannot be elongated

Question 14

What drug is 10x more potent against HSV 1 and 2 than against VZV?

Answer 14

Acyclovir

Question 15

What are the best drugs to treat varicella zoster virus from best to worst?

Answer 15

Famciclovir> Valacyclovir»»>acyclovir

Question 16

What drug is used when viral kinases have mutated to avoid cyclovirs and inhibits viral DNA polymerase enzymes?

Answer 16

Foscarnet

*IV only, nephrotoxicity

Question 17

What drug is used for prophylaxis and treatment of influenza A and B viruses? When should this drug be administered? How many days of symptoms does it save?

Answer 17

Oseltamivir (Tamaiflu) neuroaminidase inhibitor

*early administration (within 48 hours) is crucial. Disulfuram like reaction

saves 1-2 days

Question 18

Which drug is an antiviral and a weak anti-parkinsons drug and is effective against influenza A only? why is this drug no longer used? What are the contraindications for this drug?

Answer 18

Amantadine (blocks biral penetration/uncoating M2 Proteins)
No longer used because there is nearly 100% resistance in influenza A for this drug
contraindicated for patients with renal impairment or pregnant

Question 19

if antigenic drift causes viral resistance to develop it leads to epidemics. this phenomenon is called??

Answer 19

antigenic shifts

Question 20

how long is Chicken pox usually contagious?

Answer 20

lasts 1-2 days pre-rash until all lesions are gone. about 7-10 days total

Question 21

stress, fatigue, sun exposure, surgery, fever, mentrual periods or being immunocompromised are all common triggers for what?

Answer 21

reactivation of latent herpes viruses

Question 22

age related decline in immune function is called what?

Answer 22

immunosenescence

Question 23

Acyclovir is more potent against which herpes viruses over which other one?

Answer 23

10 times more potent against HSV1 and 2 than VZV

Question 24

Which cyclovir drug for HSV and VZV is converted to acyclovir in the body and thus has a greater concentration than acyclovir and is prescribed for oral use only?

Answer 24

Valacyclovir

Question 25

Which cyclovir drug for HSV and VZV is topical only due to poor oral absorption?

Answer 25

penicyclovir

Question 26

Famcyclovir is metabolized to what drug? What infections is it mainly used for?

Answer 26

Penicyclovir

used mainly for VZV

Question 27

When giving a patient a cyclovir for an HSV or VZV infection what must you make sure they do to avoid crystalline nephrophathy

Answer 27

they must hydrate well

Question 28

What is the mechanism for Zanamivir? How is the drug administered? what kind of reaction does it have with alcohol? What patients is it contraindicated in and why

Answer 28

the mechanism is a neuraminidase inhibitor
available as an inhaler only
has a disulfuram-like reaction
contraindicated in patients with severe asthma, COPD or allergies to milk proteins because it can cause bronchospasm that can cause death in these patients