HIV Infection & AIDS

Question 1

How is HIV spread?

Answer 1

blood/semen/body fluids & mother to baby

Question 2

What is the replication cycle for HIV?

Answer 2

1. Attachment to CD4 receptor on T4 lymphocyte
2. Penetration
3. Convert RNA to DNA via reverse transcriptase
4. DNA incorporated into host DNA chain via integrase
5. Latent phase (asymptomatic w/viral replication)
6. Provirus activated by protease & release from host cell
7. Host cell killed but not replicated virus

Question 3

What are the goals for HIV therapy?

Answer 3

1. reduce HIV-related death
2. improve quality of life
3. restore/preserve natural immunity
4. suppress plasma HIV viral load
5. prevent transmission

Question 4

CD4 count

Answer 4

When CD4 counts fall below 200 cells/cm3, patients are at high risk for opportunistic infections

Question 5

HIV RNA in the blood

Answer 5

Used to determine viral load; GOAL: reduce to <200 copies/mL

Question 6

Reasons for virologic failure

Answer 6

1. emergence of new HIV strands
2. adverse effects of meds
3. lack of adherence to therapy
4. drug interactions (w/food, supplements, or other meds)

Question 7

What is required for antiretroviral therapy to be successful?

Answer 7

aggressive tx w/multiple drugs from several classes at a time

Question 8

Limitations of antiretroviral therapy

Answer 8

1. bioavailability greatly impacted by food (some increase and others decrease absorption)
2. most metabolized by the liver (can increase or decrease metabolism)

Question 9

Reverse transcriptase inhibitors

Answer 9

PRODRUG; chemically resemble building blocks of DNA; “trick” enzyme to manufacture DNA using drug

Question 10

Nonnucleoside reverse transcriptase inhibitors

Answer 10

cause change in shape of enzyme molecule so enzyme can no longer add to viral DNA strand

Question 11

Protease inhibitor

Answer 11

prevent HIV protease from completing the final step in HIV maturation

Question 12

Integrase inhibitor

Answer 12

blocks integrase from incorporating viral DNA into host chromosome

Question 13

Entry inhibitor

Answer 13

block the entry of viral nucleic acid into T4 lymphocyte

Question 14

zidovudine (AZT, Retrovir)

Answer 14

antiretroviral, nucleoside reverse transcriptase inhibitor
USE: tx of HIV w/other meds
MOA: “tricks” reverse transcriptase = defective DNA
AE: headache, anorexia, nausea, diarrhea, fatigue, generalized weakness
BLACK BOX WARNING: fatal lactic acidosis, myelosuppression, and myopathy
Breastfeeding not recommended

Question 15

efavirenz (Sustiva)

Answer 15

antiretroviral; non nucleoside reverse transcriptase inhibitor
USE: tx of HIV w/other meds
MOA: binds directly w/reverse transcriptase = prevent DNA synthesis
AE: CNS effects in at least 50% of pt’s (sleep disorders, nightmares, decreased concentration, and delusions); rash also common
Pregnancy: can cause neural tube defects
NC: decreased absorption when taken w/food

Question 16

lopinavir w/ritonavir (Kaletra)

Answer 16

antiretroviral; protease inhibitor
USE: tx of HIV w/other meds; one increases concentration of another
MOA: inhibits HIV protease
AE: diarrhea, headache, GI related effects; can worsen hyperglycemia in pt’s w/DM
NC: increased absorption when taken w/high fat meals