Anti-virals

Question 1

Anti-Herpes Agents

Answer 1

• Acyclovir - Valacyclovir
• Penicyclovir - Famcyclovir
• Gancyclovir - Valgancyclovir

Question 2

Acyclovir

Answer 2

• prototype anti-herpes drug
• guanosine analogue
• good CSF penetration
• acyclovir –TK–> monophosphate –cellular enzymes–> triphosphate (active form)
• low activity for CMV

MOA: DNA Chain terminator

Question 3

[T/F] Acyclovir is used to treat all kinds of fungal infections.

Answer 3

F. Only for severe or life-threatening diseases caused by HSV and VZV.

Question 4

Acyclovir: Resistance (4)

Answer 4

• TK-negative mutants
• TK-partial mutants
• TK-altered mutants
• DNA-polymerase mutants

Question 5

**[T/F] **Acyclovir is given with a loading dose.

Answer 5

T. Usually given with a loading dose because of its low bioavailability.

Question 6

Varicella treatment: High risk for moderate to severe conditions

Answer 6

ORAL

• >12y/o
• chronic cutaneous/pulmonary disorders
• receiving short-term salicylate therapy
• receiving short, intermittent or aerosolized course of corticosteroids
• pregnant women in 2nd or 3rd trimester

INTRAVENOUS

• ​for immunocompromised patients
• pregnant with serious complications

Question 7

HSV Treatment

Answer 7

Neonatal: regardless of manifestations –> IV acyclovir

Genital: oral (IV for severe) acyclovir or valacyclovir for primary, intermittent or long term suppression therapy for recurrent

Mucocutaneous: IV acyclovir for immunocompromised, oral for immunocompetent

Question 8

Gancyclovir

Answer 8

• synthetic guanosine analog
• suppress viral DNA polymerase
• effective on CMV
• very toxic –> DO NOT USE UNLESS IT’S AN EMERGENCY!

Question 9

[T/F] Valgancyclovir should not be given within 72hrs of getting the rash.

Answer 9

F. It should be given within 72hrs of getting the rash for it to have some benefits.

Question 10

Critical steps in viral reproduction that are potential targets of antiviral drugs.

Answer 10

• Attachment
• Co-receptor binding
• Fusion

Question 11

Classes of Antiviral drugs - example

Answer 11

• NRTI - AZT
• NNRTI - Nevirapine
• Protease inhibitors - Atazanivir
• Integrase inhibitors - Raltegravir
• Entry inhibitors - Maraviroc
• Fusion inhibitors - Enfurvitide

Question 12

NRTI: MOA

Answer 12

inhibit reverse trnscriptase by being incorporated into the newly synthesized viral DNA

Question 13

NRTI: Adverse Effects

Answer 13

• lactic acidosis
• hepatic steatosis
• dyslipidemia

Question 14

NNRTI: MOA

Answer 14

noncompetitively inhibit HIV reverse transcriptase by binding to a site distant from the enyme’s active site

Question 15

Protein inhibitors: MOA

Answer 15

prevent maturation of virus protein by competitively inhibiting HIV proteases

Question 16

Most recommended protein inhibitor?

Most recommended drug combination in PH?

Answer 16

• Atazanivir
• Lotanivir + Ritonavir

Question 17

Initial Antiretroviral therapy (WHO 2013)

Answer 17

• 2NRTI’s and NRTI
  
  • TDF + 3TC (or FTC) + EFV

Question 18

First line antiretroviral regimen in PH

Answer 18

• 2NRTI (AZT + 3TC) + NNRTI (NVP)

Alternate first line NRTI:

• TDF + 3TC
• d4T + 3TC when TDF and AZT are contraindicated

Alternate first line NNRTI:

• EFV

Question 19

Second line antiretroviral regimen in PH

Answer 19

• 2NRTI’s + LPV/r
  
  • AZT + 3TC + LPV/r of prev on TDF
  • TDF + 3TC + LPV/r if prev on AZT or d4T

Question 20

Anti-influenza agents: Neuraminidase inhibitors

Answer 20

Zanamivir

Oseltamivir

Question 21

**[T/F] **Oseltamivir has a higher bioavailability than Zanamivir.

Answer 21

T