HIV Prophylaxis

Question 1

Treatment following Needle Stick

Answer 1

ZDV + 3TC (1 month)

High risk (e.g., high viral RNA copies):

ZDV + 3TC + indinavir

ZDV = zidovudine, 3TC = lamivudine

Question 2

Treatment during Pregnancy

Answer 2

ZDV full dose (2^nd and 3^rd trimester + 6 weeks to neonate)

Reduces vertical transmission by 80%

Recall: ZDV restricted to intrapartum period or NNRTI (nevirapine) one dose at onset of delivery + one dose to neonate can reduce transmission by 50-60%

Question 3

Fusion Inhibitors

Answer 3

Enfuviritide and Maraviroc

Question 4

How does enfuvirtide work?

Answer 4

Binds gp41 and inhibits fusion of HIV to CD4+ cells

(steric hinderance)

Question 5

How does maraviroc work?

Answer 5

Blocks CCR5 protein on macrophage surface to prevent viral entry

Question 6

Why do fusion inhibitors target gp41 and not gp120?

Answer 6

gp120 quickly mutates

Question 7

CCR5 Mutations

Answer 7

Homozygous = immune to HIV

Question 8

CXCR4 mutations

Answer 8

Detrimental effects (NOT analogous to CCR5 mutations)