Antivirals- Herpes and CMV

Question 1

4 anti-herpes virus agents

Answer 1

Acyclovir
Valacyclovir
Famciclovir
Penciclovir

Question 2

Acyclovir will interact with ___(enzyme)___ converting it to _____.

Answer 2

Herpes thymidine kinase

Acyclovir monophosphate

Question 3

What active metabolite would compete with deoxyGTP for incorporation in the viral DNA?

Answer 3

Acyclovir triphosphate

Question 4

Why would there be chain termination and abortion of elongation with acyclovir?

Answer 4

Because it lacks the 3-hydroxy group

Question 5

What will be the effect of probenicid and cimetidine to acyclovir clearance?

Answer 5

Decrease clearance

Question 6

Somnolence and lethargy is observed if acyclovir is administered with?

Answer 6

Zidovudine

Question 7

MOA of acyclovir

Answer 7

Inhibit viral DNA synthesis

Question 8

Which anti-herpes drug is widely distributed in body fluids?

Answer 8

Acyclovir

Question 9

Mechanism of clearance of acyclovir

Answer 9

Glomerular filtration and tubular secretion

Question 10

Oral acyclovir is indicated for?

Answer 10

• Genital herpes

- Primary herpetic gingivostomatitis

Question 11

IV acyclovir is indicated for?

Answer 11

• Herpes simplex encephalitis
• Neonatal HSV infection
• Serious HSV and VZV infections

Question 12

Valacyclovir is an ______ ester.

Answer 12

L-valyl ester

Question 13

Valcyclovir is rapidly converted to acyclovir after ____ administration.

Answer 13

Oral

Question 14

Clinical uses of valcyclovir

Answer 14

First or recurrent genital herpes

Varicella and zoster infections

Question 15

Half-life of famciclovir and penciclovir increases with what disease

Answer 15

Renal insufficiency

Question 16

Elimination of famciclovir and penciclovir

Answer 16

Glomerular filtration and tubular secretion

Question 17

Famciclovir is the prodrug of?

Answer 17

Penciclovir (6-deoxypenciclovir)

Question 18

Route of admin for famciclovir

Answer 18

Oral

Question 19

Clinical uses of famciclovir

Answer 19

HERPES LABIALIS
First and recurrent genital herpes
Chronic daily suppression of genital herpes
Acute herpes zoster

Question 20

Effect of probenicid to penciclovir

Answer 20

Increases levels of penciclovir

Question 21

ADR of famciclovir

Answer 21

Headache, nausea, diarrhea
Confusion (elderly)
Hallucinations, urticaria

Question 22

What type of analog is penciclovir?

Answer 22

Acyclic guanine nucleoside

Question 23

What are the acyclic guanine nucleoside analogs?

Answer 23

Acyclovir
Penciclovir
Ganciclovir

Question 24

MOA of penciclovir

Answer 24

Inhibitor of viral DNA synthesis

Question 25

What enzyme phosphorylates penciclovir?

Answer 25

Viral thymidine kinase

Question 26

Dosage form of penciclovir

Answer 26

Topical cream

Question 27

Clinical use of penciclovir

Answer 27

Herpes labialis

Question 28

3 agents to treat cytomegalovirus infections

Answer 28

Ganciclovir Valganciclovir Foscarnet

Question 29

Spectrum of activity of ganciclovir

Answer 29

All herpes viruses, especially active against CMV

Question 30

Dosage form of ganciclovir

Answer 30

IV and intravitreal injections

Question 31

Elimination of ganciclovir

Answer 31

90% eliminated unchanged by glomerular filtration and tubular secretion

Question 32

Clinical uses of ganciclovir

Answer 32

``` CMV retinitis CMV colitis esophagitis pneumonitis Reduce risk of CMV infection on transplant recipients Kaposi’s sarcoma in AIDS patients ```

Question 33

What enzyme facilitates the conversion of ganciclovir to ganciclovir monophosphate in CMV?

Answer 33

Protein kinase pUL97

Question 34

Mechanisms of resistance in ganciclovir

Answer 34

Mutations in viral phosphotransferase | Mutations in viral DNA polymerase

Question 35

ADRs in ganciclovir

Answer 35

MYELOSUPPRESSION Nausea, diarrhea, fever, rash, headache, insomnia, peripheral neuropathy Vitreous hemorrhage and retinal detachment

Question 36

Effect of trimethoprim and probenicid to ganciclovir

Answer 36

Increased ganciclovir levels

Question 37

Effect of ganciclovir to didanosine

Answer 37

Increased didanosine levels

Question 38

What type of ester prodrug is valganciclovir?

Answer 38

L-valyl ester

Question 39

Valganciclovir is rapidly hydrolyzed to ganciclovir via what enzymes

Answer 39

Esterases

Question 40

Esterases are found where?

Answer 40

Intestinal wall and liver

Question 41

Elimination of valganciclovir

Answer 41

Renal elimination - glomerular filtration and tubular secretion

Question 42

Clinical uses of valganciclovir

Answer 42

CMV retinitis | Prevention in transplant recipients

Question 43

What type of analog is foscarnet?

Answer 43

Inorganic phosphate analog

Question 44

MOA of foscarnet

Answer 44

Inhibit viral nucleic acid synthesis

Question 45

Foscarnet reversibly blocks what binding site?

Answer 45

Pyrophosphate binding site

Question 46

What specific mechanism is inhibited by foscarnet?

Answer 46

Cleavage of pyrophosphate from deoxynucleotide triphosphate

Question 47

Dosage form of foscarnet

Answer 47

IV | Intravitreal

Question 48

True or False: Foscarnet could be deposited in bone.

Answer 48

True, 30% could be deposied in bone

Question 49

Elimination of foscarnet

Answer 49

Glomerular filtration and acute tubular secretion

Question 50

Clinical uses of foscarnet

Answer 50

End organ CMV diseases (retinitis, colitis, esophagitis) Ganciclovir-resistant diseases Acyclovir-resistant HSV and VZV infections CMV retinitis in AIDS patients

Question 51

ADRs of foscarnet

Answer 51

RENAL IMPAIRMENT Hypocalcemia Genital ulcerations

Question 52

What ADR is expected when foscarnet is co-administered with pentamidine?

Answer 52

Severe hypocalcemia

Question 53

What ADR is expected when foscarnet is co-administered with zidovudine?

Answer 53

Risk of anemia

Question 54

What ADR is expected when foscarnet is co-administered with imipenem?

Answer 54

Risk of seizures