Strategies for first line HIV therapy

May 2008     View PDF     En español

NNRTIs

NNRTIs work differently than NRTIs, but they act against HIV at the same place in its replication cycle. In first line therapy, NNRTIs are regularly used with two NRTIs. Regimens with Sustiva (efavirenz) have been compared to several other combinations and have consistently proven both potent and long-lasting. Sustiva is listed in the Guidelines as a preferred first line drug.

Even though the Guidelines recommend Sustiva over Viramune (nevirapine), Viramune may be preferred at times. This is mainly true for people who wish to save PIs for later, but who are concerned about the brain-related (neurological) side effects of Sustiva. These may include vivid and disturbing dreams, difficulty concentrating, insomnia and mood changes. In studies, 14–53% of people who took Sustiva reported these side effects. Most doctors report higher rates of these side effects in their patients.

Viramune is listed as an alternative, mostly due to its risk of serious liver toxicity. This happens mostly in people who start it at higher CD4 counts: over 250 for women and 400 for men. Viramune should not be started in people with CD4 counts higher than this.
The risk for rashes from Viramune appears to be slightly higher in women than men. Among women who develop the rash, it’s more likely to be severe. However, pregnant women and women trying to get pregnant should avoid Sustiva. If their CD4 counts are below 250, they may consider Viramune a better option when starting a regimen without a protease inhibitor.

The most recently approved NNRTI, Intelence (etravirine) has not been studied in people taking HIV drugs for the first time. Therefore, it should not be used in this way.

One important point to keep in mind is that Sustiva, Viramune and Rescriptor (delavirdine) are highly cross resistant. This means that when HIV becomes resistant to one of them, it will likely be resistant to the others, making them less useful. Of the four NNRTIs, Rescriptor is used the least often. This is because it’s taken three times a day and interacts with many other meds. Rescriptor has not been well studied either, especially in people on first line therapy.