hi! i need to know if we can use a convination of : azt+3tc+crixivan+sustiva mean all in one regimen, and if its more powerfull of azt+3tc+crixivan , with out sustiva?? thanks .

Each active medication in a combination of meds adds additional power. So, yes, Sustiva, if active, would add power to the three drug combo you mention.

But here are the issues - since you don't mention much/any background. If, for example, you already have some degree of resistance to any of the nonnucleoside class, of which Sustiva is one of three available - then adding Sustiva won't do anything, other than perhaps some vivid dreams.

And that general lesson is true with most of these meds. Although with some, past use and resistance decreases their power, but doesn't eliminate it entirely. This is however a big issue for the nonnukes - where past use and resistance to any one almost always means none of them have any power to offer.

Without knowing more about the background it is hard to comment much more on the specific combo you mention - and why you are asking about these four. But hopefully these few comments are helpful to you.