• Resistance is an important reason why anti-HIV drugs stop working.
  • HIV which is resistant to one drug may also be resistant to other drugs which you haven't taken yet.
  • The chance of developing resistance will be reduced if your viral load while on treatment is undetectable, and you take every dose of the drugs prescribed to you at the correct time and in the correct way.
  • The more you miss doses, the more likely it will be that your drug combination will fail.
  • Some people contract HIV which is drug resistant when they become infected. A small number of people have been superinfected with resistant virus.
  • Resistance tests can be used to help choose replacement drugs if your anti-HIV drug combination is not controlling your viral load.