How can one go about stopping a successful combo that consisting of once a day sustiva, abacavir and 3tc without developing resistance.

Thanks for your question.

The question that you raise is based on the idea that efavirenz (Sustiva, Stocrin) stays around in the body longer than either abacavir or 3TC after treatment is discontinued. Unfortunately, we don't have a clear-cut answer-- but it is reasonable to be concerned about the risk of NNRTI resistance in this circumstance. Indeed, studies of single dose nevirapine in pregnancy have clearly raised this possibility, with a high percentage of women acquiring drug resistance.

In practical terms, if your were my patient, I'd probably stop the abacavir/3TC a day before the efavirenz. This is based on pure, seat-of-the-pants medicine and is without any sure clinical trials experience. Another approach that some doctors have discussed is to switch you (briefly) from efavirenz to a protease inhibitor prior to discontinuation. This idea is based on the idea that the protease inhibitor's metabolism is likely to be more similar to abacavir/3TC than efavirenz; the three drugs could then be discontinued at the same time.

I hope this helps, BY