B3.012 Prework 2 VZV Treatment and Management

Question 1

mode of action of acyclovir

Answer 1

phosphorylated by viral thymidine kinase (TK1) to acyclovir monophosphate and then by cellular enzymes to acyclovir diphosphate and triphosphate
acyclovir triphosphate is a competitive inhibitor of viral DNA synthesis
chain terminator

Question 2

how is valacyclovir converted to acyclovir

Answer 2

valine ester, pro-drug

cleaved by esterases to yield acyclovir

Question 3

how does valacyclovir differ from acyclovir in its action

Answer 3

higher bioavailability: serum levels 3-5x those obtained with oral acyclovir
dosed twice/day instead of 3-5x
more expensive

Question 4

mechanism of action of famciclovir

Answer 4

prodrug of penciclovir
phosphorylated by viral thymidine kinase
converted to penciclovir triphosphate which competitively inhibits HSV-2 polymerase

Question 5

varivax facts

Answer 5

live attenuated viral vaccine

indicated for active immunization for the prevention of varicella in individuals 1 year and older

Question 6

types of vaccines for chickenpox

Answer 6

monovalent

combination

Question 7

vaccine antigens in monovalent chickenpox vaccine

Answer 7

live attenuated Oka strain

propagated in MRC5 human diploid cells

Question 8

vaccine antigens in combination chickenpox vaccine

Answer 8

live attenuated OKA strain propagated in MRC5 human diploid cells, plus measles, mumps, and rubella

Question 9

zostavax vs. varivax

Answer 9

zostavax intended for patients >60 years to reduce risk of getting shingles
varivax intended for people who have not had chicken pox to prevent them from acquiring the infection
both same virus, but zostavax has a higher dose

Question 10

summary of adverse effects of the Varivax vaccine

Answer 10

rashes within 42 days of vaccine
reports of breakthrough varicella
herpes zoster
neurologic AEs have been reported in the post-marketing environment
secondary transmission
OVERALL SAFE AND WELL TOLERATED

Question 11

what stem cell lines are present in the VZV vaccine?

Answer 11

WI-38

MRC-5

Question 12

different types of stress which can induce VZV reactivation

Answer 12

GI issues
high BP
obesity
heart disease
diabetes
difficulty sleeping
chest pain
headaches
changes in sex drive
changes in mood
overeating/undereating
substance abuse

Question 13

main risk factors for getting shingles

Answer 13

having chicken pox
people who have had vaccine are still at risk tho
most people are over 50
weakened immune system

Question 14

what immune system affecting conditions/treatments can make you more susceptible to shingles?

Answer 14

HIV
immunotherapy treatment for people w organ transplants
cancer
cancer treatments
polymorphisms in genes that render the cells unable to mount antiviral responses

Question 15

conservative therapy for VZV

Answer 15

non steroidal anti-inflamms (NSAIDs)
wet dressings w 5% aluminum acetate applied for 30-60 min 4-6 times daily
lotions

Question 16

primary medications for acute zoster associated pain

Answer 16

narcotic and nonnarcotic analgesics
neuroactive agents
anticonvulsant agents

Question 17

how does antiviral therapy affect the course of herpes zoster?

Answer 17

may decrease the length of time for:
 new vesicle formation
complete crusting
acute discomfort
earlier meds are started, more effective they are (within 72 hours of onset)

Question 18

pathologic observations thought to distinguish postherpetic neuralgia from uncomplicated zoster

Answer 18

axonal and cell body degeneration
atrophy of the spinal cord dorsal horn
scarring of the dorsal root ganglion
loss of epidermal innervation of the affected area