i'm taking sustiva hs and combivir bid. i usually take the sustiva before bed around 11pm, the combivir at 8am and 8pm. how much time frame do i have to take the dosages or must they be percise?

Good question. The answer is that it is different for every drug. Sustiva has a very long half life, meaning it stays in the body for many days. Therefore, you do not have to be very precise at all in the timing of sustiva, as long as you get in a dose every day. At the other extreme is crixivan (without ritonavir) where the timing is very important. We don't have an exact answer for combivir, because it is the timing of the levels inside of cells that matters, and that is very difficult to measure. None the less, we think that you have few hours slack in either direction. To be concrete, if you forgot your 8PM combivir and took it at 11PM with the Sustiva, it would probably be fine. Similarly, if you found that taking the combivir at 8AM and 9M with Sustiva at 9PM worked for you, that should be fine. It is most important that you have a regimen that you can remember and stick with. Good luck

ATP