The goal of anti-HIV treatment is an undetectable viral load (below 50 copies/ml of blood in the tests used in most HIV clinics).

If your viral load is above this level then HIV is continuing to reproduce. Your viral load may fall to undetectable levels and then become detectable again, if this happens in two consecutive tests you should change treatment.

Treatment which is not suppressing viral load to undetectable levels should be changed if there are other drug combinations available to you which are likely to achieve this.

Your treatment is also considered to be failing if you have achieved an undetectable viral load and then have two viral load tests at least two weeks apart which both show that viral load is above 50.

If there are other drugs available to you that give you the chance of getting an undetectable viral load, and will be able to tolerate these drugs and take them properly, then you should consider switching therapy.

Your choice of replacement drugs should also be guided by the results of a resistance test and your previous treatment history.

Sometimes your viral load may rise to just above the detectable level and then fall back below on the next test. This is called a 'blip', and means that your viral load should be re-tested as soon as possible, ideally within two weeks. Though one-off blips may be caused by a problem with viral load testing itself, they should also be a trigger to consider other possible causes, such as drug interactions, adherence problems, illnesses or vaccinations. Regular blips may be a sign that your treatment is more likely to fail.

If your treatment is being changed because of side-effects, but your viral load is below 50 copies/ml, it is okay to switch only the drug(s) causing problems.

If you have had problems taking your drugs regularly, known as a adherence, your failing treatment regimen should ideally be replaced with drugs that are easier to take, and support with adherence should be provided to you. For more information on the steps you can take to improve your adherence see the booklet in this series called Adherence.

 

Changing your treatment after more than one treatment failure

Doctors often make a distinction when talking about people who need to change their HIV drugs for the first time and those who've already made changes before because of the failure of their treatment to control viral load or an increase in viral load on more than one occasion. The term "salvage therapy" is often used to describe treatment if you have already taken drugs from all the major anti-HIV drug classes.

Ideally your new treatment should include two, preferably three new drugs, at least one from a new class.

A number of new anti-HIV drugs have recently become available. It is harder for HIV to become resistant to some of these drugs than many of the older anti-HIV drugs. Some of the new drugs work against HIV in a completely different way to older anti-HIV drugs. These drugs are therefore important new treatment options for people who have taken a lot of anti-HIV drugs in the past and have drug resistant virus.

The new anti-HIV drugs that are important treatment options for people who’ve taken a lot of anti-HIV drugs in the past are:

**Darunavir (Prezista)/ritonavir.

**Maraviroc (Celsentri).

**Raltegravir (Isentress).

**Etravirine (approval expected later in 2008).

T-20 (enfuvirtide, Fuzeon) has been available for a number of years, but it is still an important treatment option for some people.

Doctors now believe that better standards of HIV care, for example the use of resistance tests and these new drugs mean that an undetectable viral load should be the goal of everybody taking anti-HIV treatment.

But even if you cannot get an undetectable viral load, even quite small falls in viral load can mean that you have a reduced risk of illness or death. Maintaining your CD4 cell count is also likely to be a priority in these circumstances.

Treatment breaks (often called structured treatment interruptions or drug holidays) are not recommended particularly if you are taking “salvage therapy.”

“Recycling” drugs (taking a treatment that you’ve previously developed resistance to) might be of benefit in some circumstances, and there is evidence that 3TC has some anti-HIV effects and benefits even if the virus has developed resistance to it.

In some instances it is necessary to remain on a “failing” combination in the short-term until an effective combination can be found. You’ll need expert management, which takes into account your individual treatment history and drug resistance profile.