Introduction to Antiretrovirals

1
Introduction to Antiretrovirals
2
ART Eligibility Criteria

• CD4 below 200 cells/mm³
• or
• WHO stage 4 (or any AIDS defining condition)
• AND
• Psychosocial assessment likelihood of being
  able to take drugs correctly (family support, no
  untreated depression or alcohol abuse)

3
Natural History of HIV Infection
Viral Load
Number of CD4 cells / Viral Load
CD4 Count
0
2
2
4
6
8
10
6
4
Weeks
Years
4
CD4 Count and Infection
1000
Tuberculosis, Herpes zoster (shingles)
500
Oral candida, Herpes simplex, Bacterial pneumonias
200
Pneumocystis carinii (PCP)
100
Toxoplasmosis, Cryptococcus, Esophageal candida,
Histo, Kaposis
50
Cytomegalovirus (CMV)
Time
5
How Does HIV Work?
3. Integration into host cells nucleus
HIV
4. Reproduction of viral components
1. Attachment to host cell

• Assembly of new HIV viruses

2. The virus changes from RNA to DNA
CD4 CELL or T CELL
6
Antiretrovirals

• There are 3 main groups of ARVs
• NRTIs - Nucleoside Reverse Transcriptase
  Inhibitors
• NNRTIs - Non-nucleoside Reverse Transcriptase
  Inhibitors
• PIs - Protease Inhibitors

7
Action of ARVs

• NRTIs
• Latch on to strand of DNA that reverse
  transcriptase is trying to build
• NNRTIs
• Attach to reverse transcriptase and prevent it
  from working
• PIs
• Prevent the protease enzyme from assembling
  the new viral particles

8
HAART

• ART Anti-Retroviral Therapy
• HAART Highly Active Anti-Retroviral Therapy
• HAART means using 3 drugs and is sometimes called
  Triple Therapy
• If only 1 or 2 drugs are used, there is a greater
  chance of resistant strains of HIV developing

9
Nucleoside Reverse Transcriptase Inhibitors
10
Non-nucleoside Reverse Transcriptase Inhibitors
11
ART Regimens

• Standard Regimen
• Two NRTIs one NRTI
• Lamivudine, Stavudine
• Efavirenz (Stocrin) or Nevirapine
• Second Line (if resistance to standard)
• Two NRTIs one PI
• Zidovudine (AZT), Didanosine (ddI) Kaletra

12
Side Effects
13
McCord HIV Services

• Routine HIV tests in Outpatients ?
• CD4 test ? Wellness programme (Hope House)
• ? Preparation for ARVs (Hope House)
• Initiation of ARVs and follow up management
  (Ridge House)
• All children diagnosed with HIV are managed at
  Ridge House (preferably referred the same day)
• PMTCT programme (2-3 transmission rate)
• Siyaphila (In-patients initiated on ARVs)

14
Patient Information

• Take the drugs at the right time
• Never miss a dose
• If you forget, take the dose as soon as you
  remember. Then continue with your normal dosing
  times.
• If you forget altogether, do not take a double
  dose the next time
• If you go away for the weekend, take your drugs
  with you

15
Patient Information ..

• Make sure you dont run out of tablets
• If you are worried about anything in relation to
  your drugs, speak to the doctor
• Dont stop any drugs without speaking to the
  doctor
• Dont combine ARVs with immune boosters or
  traditional medicines. Some of them interfere
  with the action of the ARVs.

16
Resistance

• The main reason for the virus to become resistant
  to the drugs is failure to take the drugs
  correctly
• Resistance to one drug often means resistance to
  other drugs in that group
• Once resistance develops, other drugs have to be
  used
• If further resistance develops, there are few
  options for effective treatment.

17
Main Message for ARVs

• Take all the drugs correctly all the time!

18
Recommended Initial Regimen