Monitoring therapy:
-
Check plasma viral load every
6 months.
-
If viral is undetectable (generally
meaning <20 copies/ml), check CD4 count
every 6-12 months.
-
Change drug regimen if viral
load increases 3-5 fold.
-
The new regimen should include
antiviral drugs the patient has not previously received.
-
Viral load >200 copies/ml generally means
treatment failure.
- Critical to do genotyping.
-
Sequence genes for RT, protease and integrase looking for mutations that confer
resistance.
-
Prescribe three drug regimen for which virus is sensitive.
-
Once
resistant always resistant.
Most patients harbor different "strains" of HIV with different sensitivities.
If a patient takes their medicine inconsistently and develops resistance,
checking a genotyping a few months later will often show the "wild type" virus
has reemerged.
In general, if treatment is failing, you want to do a genotyping test while
the patient is still on the failing meds.
|