YOU ARE HERE:
Why is adherence important?
   Last updated: 23.05.05
 
  • Adherence is the most important element in the success of your anti-HIV treatment.


  • Low levels of adherence to HAART lead to the drugs not working effectively and are associated with increases in viral load, a fall in CD4 count, increased risk of disease progression, more time in hospital and an increased risk of death.


  • Adherence is particularly important in HIV infection because you can quickly become resistant to anti-HIV drugs if you do not take them at the right times and because cross-resistance (becoming resistant to similar drugs) limits your future treatment options. Missing doses, taking your doses late or early, taking the wrong doses, or taking a drug in such a way that you absorb too little of it may lead to the development of resistance to your drugs. This is because HIV can develop resistance to a drug if the blood level of the drug is too low to stop the virus from reproducing. As HIV continues to replicate, strains of virus which are able to continue to reproduce despite the drug's presence (drug resistant strains) gain a competitive advantage over the strains of HIV that your medication is still effective against, and form the basis of the HIV in your body. The booklet in this series, Resistance contains more information.


This can have potentially serious results, such as:
  • You develop viral resistance, which means that your treatments are likely to stop working and your chance of becoming ill because of HIV is increased, as the amount of HIV in your blood increases and your CD4 count falls.

  • You may need to change your HIV treatments, which might include more drugs, be more difficult to take, and have more or new side-effects.


You may become resistant to drugs similar to those you are currently taking. For example, people who become resistant to one NNRTI are usually resistant to all currently available drugs in this class. This is called 'cross-resistance' and the risk varies from drug to drug but it can happen in all the classes of drug used to treat HIV.
Because adherence is so important, some doctors think that it is better for your health to stop treatment completely if you are unable to adhere properly.
It is important that you are aware of the general risks of stopping treatment, and talk to your doctor about whether this is an option for you. Your doctor should talk to you about regular monitoring to reduce the risk that your CD4 count will fall to a level at which you could develop AIDS-defining illnesses.

This is because:
  • Your CD4 count is likely to fall back to its pre-treatment level within six months or less, regardless of how high it is now, and will continue to fall after that point.

  • If you had an AIDS-defining illness before you started combination therapy, you are five times more likely to experience a CD4 decline back below 200 cells (the at-risk level for further AIDS-related illnesses) than someone who started treatment with a higher CD4 count.

  • If you stopped treatment with a CD4 count below 200, you are at risk of developing AIDS-defining illnesses immediately and should discuss with your doctor whether you need to take medication to prevent infections (prophylaxis) before you stop combination therapy.

  • If you are taking a drug such as efavirenz, 3TC, or nevirapine, which take a long time to clear out of the body, you run the risk of developing resistance during the withdrawal period. If you start treatment again with the same drug, it may no longer work.