Pharmacology

Question 1

Who gets to receive HIV treatment

Answer 1

ALL HIV + patients

Question 2

Name 3 instances when you delay HIV treatment

Answer 2

1. Cryptococcal meningitis (give 4-6 weeks anti-fungals)
2. TB meningitis (give 8 weeks TB meds)
3. Non- neurological TB (CD4+ T <50 2 weeks & >50 8 weeks)

Question 3

What is the 4 purposes of the treatment

Answer 3

1. Suppress viral load
2. Preserve immune function
3. Decrease morbidity & mortality
4. Increase & improve QOL

Question 4

Name 3 people to who you give preventative treatment

Answer 4

Sexual exposure
Occupational exposure
MTCT

Question 5

What is the ARV regimen called & consists of

Answer 5

HAART- highly active antiretroviral therapy
Combination of 3 drugs= 2 NRTI + PI/NNRTI/InSTI
Life long therapy

Question 6

What drugs does pre exposure prophylaxis consist of & when do you drink it

Answer 6

2 drugs, tenofovir & emtricitabine, for duration of exposure

Question 7

How does post exposure prophylaxis work

Answer 7

3 drugs (TLD) for 28 days w/i 72 hrs of exposure

Question 8

Give 2 reasons why is adherence important & what should be considered when starting treatment

Answer 8

Important for viral suppression & preventing resistance
Treat depression/substance abuse & educate patient on importance of adherence

Question 9

What are the 5 drug classes of ARV

Answer 9

1. Nucleoside RTI (NRTI)
2. Non-nucleoside RTI (NNRTI)
3. Integrase strand inhibitor (InSTI)
4. Protease inhibitor (PI)
5. Entry blockers (CCR5 blocker)

Question 10

NRTI mechanism of action, medication & side effects

Answer 10

Mechanism:
Competitive inhibition of RT
Nucleoside still has to be phosphorylation
Medication:
Zidovudine, lamivudine & tenofovir
Side effects:
Zidovudine: anaemia, neutropenia
Tenofovir: renal dysfunction & osteopenia

Question 11

NNRTI mechanism of action, medication & side effects

Answer 11

Mechanism:
Allosteric site binding & inhibition of RT (change shape)
Nucleotide not required to be phosphorylated
Medication:
Efavirenz & niverapine
Side effects:
Efavirenz: rash, hepatotoxcity & neuropsychiatric
Niverapine: rash & hepatotoxicity

Question 12

InSTI mechanism of action, medication & side effects

Answer 12

Mechanism:
Inhibit fusion of viral & host DNA
Medication:
Dolutegravir
Side effects:
Insomnia

Question 13

PI mechanism of action, medication & side effects

Answer 13

Mechanism:
Inhibit enzyme by binding to active site & not able to produce peptides
Medication:
Lopinavir, ritonavir & atazanavir
Side effects:
Lopinavir & Ritonavir: D, hyperTG & - cholesterol
Atazanavir: unconjugated hyperbilirubinanaemia

Question 14

What drug is given for PI boosting, why & what it can lead to

Answer 14

Ritonavir is a cytochrome p450 inhibitor meaning it slows down metabolism, increasing the concentration of drugs present & reducing times medication should be taken
It can lead to toxicity if [ ] is to high

Question 15

What drug is an inducer of HIV medication & what is can lead to

Answer 15

Rifampicin for TB, increase metabolism & decrease concentration
Can lead to sub-therapeutic dosage

Question 16

3 ways how drug resistance is avoided

Answer 16

Multiple drugs/combined ARV
Good adherence
Suppress viral replication to avoid mutation

Question 17

What happens when resistance occur

Answer 17

Resistance mutations accumulation affecting a whole drug class making the virus able to transmit & less fit for the medication

Question 18

What is a resistance barrier

Answer 18

The number of virus mutations before resistance occur

Question 19

The 3 resistant barrier classes & examples

Answer 19

Low: rapid mutation causing complete resistance & NRTI/NNRTI
Intermediate: tenofovir, unboosted PI & thymidine analogues
High: multiple mutations before resistance & boosted PI & dolutegravir