Antivirals

Question 1

What type of drugs are anti-herpes virus drugs?

Answer 1

Nucleoside inhibitors of DNA polymerase

Question 2

What type of molecules are anti-herpes virus drugs?

Answer 2

Purine or pyrimidine nucleoside analogues (guanosine)

Question 3

Give 5 anti-herpes virus drugs

Answer 3

1. Aciclovir
2. Valaciclovir
3. Ganciclovir
4. Famciclovir
5. Foscarnet

Question 4

What is the mechanism of action of anti-herpes virus drugs?

Answer 4

They are converted to nucleoside triphosphate by viral and cellular kinases that are incorporated into viral DNA to decrease the rate of chain elongation, and so they are chain terminators

Question 5

What is the antiviral spectrum of anti-herpes virus drugs?

Answer 5

• Herpes simplex virus
• Varicella zoster virus
• CMV

Question 6

What is aciclovir used to treat?

Answer 6

• HSV-1
• HSV-2
• VZV

Question 7

What is the mechanism of action of aciclovir?

Answer 7

First phosphorylation step is carried by a specific viral enzyme, thymidylate kinase, which leads to chain termination, directly inhibiting DNA polymerase

Question 8

How are some viruses resistant to aciclovir?

Answer 8

• May lack thymidylate kinase (TK-)
• Possess mutations in the TK gene
• Mutations that prevent DNA polymerase from binding to acyclovir triphosphate

Question 9

For what is aciclovir the treatment of choice?

Answer 9

• Herpes simplex encephalitis
• Varicella-zoster virus infections
• Fever blisters
• Genital herpes

Question 10

How is aciclovir given when treating herpes simplex encephalitis?

Answer 10

IV

Question 11

When is aciclovir given to treat VZV infections?

Answer 11

When the patient is >50 years old

Question 12

What are fever blisters also known as?

Answer 12

Herpes labialis

Question 13

How is aciclovir given when treating fever blisters?

Answer 13

Topically

Question 14

How is aciclovir given when treating genital herpes?

Answer 14

• Topical
• Oral
• IV

Question 15

What happens when aciclovir is given to patients with renal failure?

Answer 15

It accumulates

Question 16

Does aciclovir have action against CMV?

Answer 16

No

Question 17

What are the oral analogues of aciclovir?

Answer 17

• Valaciclovir
• Famciclovir

Question 18

What is ganciclovir the treatment of choice for?

Answer 18

CMV infections, and its associated conditions

Question 19

What conditions are associated with CMV infection?

Answer 19

• Retinitis
• Pneumonia
• Colitis
• Pneumonitis

Question 20

In whom are CMV infections treated with ganciclovir?

Answer 20

Patients with AIDS, or are immunocompromised

Question 21

How is the mechanism of action of ganciclovir like aciclovir?

Answer 21

It must be activated by phosphorylation, the triphosphate form of GCV inhibits the viral DNA polymerase

Question 22

How is the mechanism of action of ganciclovir unlike aciclovir?

Answer 22

Phosphorylation of GCV is catalysed by phosphotransferase enzymes, both cellular and viral, and therefore GCV is activated in uninfected cells as well as infected cells, unlike aciclovir, which can only be activated by virally encoded TK

Question 23

In whom is ganciclovir given as prophylaxis?

Answer 23

Transplant patients

Question 24

Is the oral bioavailability of ganciclovir high or low?

Answer 24

Low

Question 25

What is the result of the low oral bioavailability of ganciclovir?

Answer 25

It must be given IV, or valganciclovir given *(much higher oral bioavailability)*

Question 26

What is the mechanism of action of foscarnet?

Answer 26

Prevents addition of nucleoside triphosphate dNTP to viral DNA, limiting the extension of the viral DNA strand

Question 27

Does foscarnet phosphorylate?

Answer 27

No

Question 28

What is foscarnet active against?

Answer 28

* HSV-1 * HSV-2 * CMV * HIV

Question 29

Why is foscarnet active against HIV?

Answer 29

Because it inhibits HIV reverse transcriptase

Question 30

What are the anti-retroviral drugs (HAART)?

Answer 30

* Reverse transcriptase inhibitors (RTIs)I * Integrase inhibitors * Protease inhibitors * Viral entry inhibitors

Question 31

What are the types of RTIs?

Answer 31

* Nucleoside RTIS (NRTI) * Non-nucleoside RTIs (NNRTI)

Question 32

How do NRTIs and NNRTIs differ?

Answer 32

NRTIs have less activity on the host DNA polymerase

Question 33

Give 5 NRTIs

Answer 33

* Zidovudine * Didanosine * Zalcitabine * Zerit * Tenofovir

Question 34

Give 3 NNRTIs

Answer 34

* Nevirapine * Delaverdine * Efavirenz

Question 35

What should NNRTIs not be used as?

Answer 35

Monotherapy

Question 36

Why should NNRTIs not be used as monotherapy?

Answer 36

Because of resistant mutants

Question 37

Give an example of a integrase inhibitor?

Answer 37

Raltegravir

Question 38

Give 4 protease inhibitors

Answer 38

* Indinavir * Saquinavir * Lopinavir * Aprenavir

Question 39

Give two viral entry inhibitors?

Answer 39

* Fuzeon * Maraviroc

Question 40

What is fuzeon active against?

Answer 40

gp41

Question 41

What is maraviroc active against?

Answer 41

CCR5

Question 42

What are the types of anti-influenza drugs?

Answer 42

* Anti-influenza A drugs * Anti-influenza B drugs

Question 43

What are the types of anti-influenza A drugs?

Answer 43

* Inhibitors of early events * Neuroaminidase inhibitors

Question 44

What is the mechanism of action of anti-influenza A drugs that inhibit early events?

Answer 44

Adamantanes *(M2 ion channel)* inhibitors

Question 45

Give two anti-influenza A drugs that are inhibitors of early events

Answer 45

* Amantadine * Rimantadine

Question 46

What type of drugs are anti-influenza B drugs?

Answer 46

Neuraminidase inhibitors

Question 47

Give 2 neuraminidase inhibitors

Answer 47

* Zanamavir * Oseltamavir

Question 48

What is the trade name of zanamavir?

Answer 48

Relenza

Question 49

What is the trade name of oseltamavir?

Answer 49

Tamiflu

Question 50

Label this diagram

Answer 50

* A - NS₂ * B - Lipid bilayer * C - NA *(Neurominidase)* * D - HA *(Hemagglutinin)* * E - M₂ *(ion channel)* * F - M₁ *(matrix protein)* * G - NP *(nucleocapsid)* * H - PB1, PB2, PA *(transcriptase complex)*

Question 51

What is neuraminidase required for?

Answer 51

* For the virus to escape the infected cell * To penetrate the mucus in the airway

Question 52

What is the M₂ ion channel important for?

Answer 52

Uncoating of the virus