ANTIVIAL DRUGS EXCEPT ARVs

Question 1

What are the antiviral drugs for herpes simplex virus

Answer 1

• Aciclovir
• Valaciclovir
• Ganciclovir
• Valganciclovir
• Penciclovir
• Famciclovir
• Foscarnet (not a po-drug)

Po-drugs are activated (phosphorylated) by viral or cellular enzymes

Question 2

Which 3 HSV drugs are guanosine derivatives?

*considering all drugs are nucleotide analogues.

Answer 2

• acyclovir
• ribavirin
• Entercavir

Question 3

What are the indications of acyclovir?

Answer 3

• Treatment of HSV (I & II), varicella zoster virus, prophylaxis of recurrent
  episodes (>6/year) of herpes genitalis

*IV admin: for severe cases e.g.
- severe herpes infections,
- disseminated herpes infections,
- herpes simplex encephalitis

Question 4

What are the drug interactions seen with acyclovir?

Answer 4

• Aminoglycosides: increased nephrotoxicity
• Probenecid: delays excretion of acyclovir

Question 5

What are the side effects of using acyclovir?

Answer 5

I.V: nephrotoxic — phlebitis at injection site
topical: burning, stinging

Question 6

Which dug is a pro-dug of acyclovir? That when metabolized by cells becomes acyclovir and follows all acyclovir mechanisms?

Answer 6

valacyclovir

*Just has an increased bioavailability than acyclovir (54-70% bioavailable than acyclovir’s 10-30%)

Question 7

What are the indications of valacyclovir?

Answer 7

Indications:

• Herpes zoster virus (shingles)
• Acute genital HSV
• Prevention & tx of recurrent herpes genitalis
• mucocutaneous HSV

Valacyclovir is useful in treatment of immunocompromised

Question 8

Which dug is an acyclovir analogues? Like it shares a structure and MOA similar to that of acyclovir

Answer 8

Ganciclovir

Question 9

What’s a drug responsible for treatment of recurrent orolabial herpes simplex virus?

Answer 9

Penciclovir

*only applied topicsl

Question 10

What’s the MOA ya penciclovir?

Answer 10

penciclovir triphosphate (active form) inhibits herpes DNA synthesis by acting as a false substrate for viral DNA polymerase

Question 11

What drug is an analogue (becomes penciclovir after metabolism) of penciclovir?

Both penciclovir and this dug are are excreted renally

Answer 11

• Famciclovir

*taken orally
Indications: recurrent genital herpes, recurrent herpes labialis