Strategies for HIV therapy

April 2008    View PDF    En español

Points for people to think about for
people who are considering HIV therapy

There are many issues to consider and discuss with your doctor before starting HIV therapy. The following are ones that you may want to consider if you’re starting therapy for the first time (first line therapy) or are switching therapy (second or third line therapy).

Reducing HIV levels as low as possible, preferably below
the level of detection, should be an important goal of therapy.

Therapy that has a larger, more consistent and longer lasting effect in reducing HIV levels and increasing CD4+ counts is more likely to produce longer lasting health and survival. People with HIV levels below the limit of detection have much longer lasting responses to HIV therapy than people with consistently detectable levels. When therapy fails to reduce viral loads to undetectable levels, it’s usually a sign that it will eventually fail. However, studies show that an occasional “blip” in viral load (a detectable reading every now and then) is not a major concern. Trends over time are more important than a single test result.

Today, viral load tests measure reliably down to 40 or 50 copies. Some older tests still in use measure down to 400 copies. Numbers below this are considered undetectable. Many researchers and doctors believe that people unable to reach undetectable levels after six months on therapy should consider either switching to a new regimen or, if HIV levels are detectable but remain very low (such as below 1,000), adding another drug. Others believe it may be okay for a person with few options to continue using a regimen if it’s controlling HIV levels at a low yet detectable level (such as below 5,000). While studies show that reaching “undetectable” viral load is best, the cost of side effects or the complexity of a regimen needed to reach this goal may not be realistic for everyone.

Using a drug exactly as prescribed is critical to success.

Using an inadequate dose, reducing the dose below prescribed levels, or failing to take it at regular intervals increases the risk of resistance. If side effects develop, it’s often better to try to overcome them than to immediately change your regimen. If they’re not manageable, it’s better to temporarily stop all the drugs rather than reduce their doses, and try to solve the problem with your doctor’s guidance. The fastest way to develop resistance is to use HIV drugs at inadequate or inconsistent doses.

Learn about drug interactions.

Given the number of drugs available to treat HIV and prevent or treat opportunistic infections and other conditions, the potential for drug interactions increases. Not only does each drug have its own possible side effects, it may also increase or decrease the benefit of other drugs. Drug interactions are not always considered when creating a treatment strategy, but they can play a major role in its success. Make sure your health provider knows about all the drugs and supplements you take, including experimental and over-the-counter products.

People considering a vacation away from home should wait
until they return before starting a new drug regimen.

When side effects occur, they often happen within the first 2–4 weeks after starting a new regimen. Many resolve over time as your body adjusts. Some, but not all, people experience mild-to-moderate side effects. A smaller percentage face moderate-to-severe side effects. People should avoid starting a new regimen right before going out of town on vacation or before engaging in major life experiences, like moving or starting a new job. In the unlikely event of serious side effects, it’s better to be closer to your doctor.

There may be some degree of cross-resistance
among the drugs in the same class.

Resistance to a drug occurs when HIV changes itself so that it’s no longer fully affected by the drug. Cross-resistance occurs when resistance to one drug causes resistance to other drugs in the same class. Resistance usually occurs when the drugs being used are not potent enough to fully stop HIV replication or when the drugs are not taken as prescribed.

For instance, someone with resistance to one of the NNRTI drugs is almost certainly going to be cross-resistant with most of the other NNRTIs (see Drug ID Chart). What this means is that once resistance to one NNRTI develops, most of the other drugs in this class are less effective, and possibly wholly ineffective.

Should I get a resistance test?

Studies show that people who choose therapy based on resistance test results along with their treatment history have longer lasting responses to HIV therapy compared to those who didn’t get them before making decisions. Some researchers propose that people get resistance tests before they start HIV therapy for the first time as well as before switching to a new regimen.

In order to run a resistance test, you must have an HIV level above 1,000. The test cannot be done accurately if your levels are below the limit of detection (<50). Also, resistance tests are likely most reliable when done while someone is on HIV therapy.

Therapy that is only partly effective speeds
the development of viral resistance.

If an HIV drug reduces viral load yet allows a measurable level of viral activity (measurable viral load), the HIV that’s still present is capable of mutating and developing resistance to that drug. When a three-drug regimen doesn’t quite succeed in stopping measurable activity, many researchers believe it may be wise to either change two of the drugs or perhaps add a fourth.

It makes sense to try and fully suppress viral replication if this can be done with a reasonable quality of life. When this cannot be achieved, people should realize they can still benefit from therapy and that long-term solutions may become apparent when other drugs become available. Again, using resistance tests may help guide which drugs are not working or which may be useful to add to a regimen.

Stopping and starting a regimen often
(like on a weekly or even bi-weekly basis) will likely
lead to an increased risk of drug resistance.

A structured treatment interruption (STI), as discussed later, may include stopping therapy for two weeks or longer, then restarting it for some period of time. It’s important for people considering an STI to be closely checked for HIV levels and CD4+ counts. Many studies show that some people experience a dramatic increase in HIV levels and decrease in CD4s. For more information, read Project Inform’s publication, Strategies for Attempting Structured Treatment Interruptions.

If you need to interrupt therapy, it’s best to stop
all drugs at the same time (except nevirapine and
efavirenz) rather than just stopping one drug.

People may need to stop taking their meds for many reasons, including side effects, drug interactions, pregnancy or their drug supply runs out. Stopping HIV drugs, if they’re all stopped at the same time, is unlikely to increase drug resistance. Because Viramune (nevirapine) and Sustiva (efavirenz) remain in the body longer than any other HIV drug, they should be stopped at least two or three days and possibly up to two weeks before stopping the others. Otherwise, there’s an increased risk of developing resistance to them.

Viral load and women

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