So the other question here, and I'm surprised no one has brought this up, is what is the trough telling us? It's a surrogate for AUC, and it actually doesn't perform all that well as a surrogate (probably underestimates the AUC in ~25% of cases). If you're using a fancy PK calculator to come up with your doses (and estimated PK parameters), why not target the thing you're actually trying to meet? Based on the sneak peaks that have been given of the upcoming vanco guidelines, AUC is going to be re-emphasized as a goal measure (and yes, that means two-level kinetics are going to be making a comeback).
The guidelines that we have now were based on the best-guess of what we should be doing, and the literature that has come out since that time suggests that the mark may have been missed somewhat. It's also worth mentioning that this literature, and really the whole guideline, applies only to S. aureus. An often overlooked fact.
As far as the vanc nephrotoxicity goes, I think it's been pretty clearly shown that there is a dose- and duration-dependent increase in nephrotoxicity with vancomycin. Whether minor creatinine bumps are clinically relevant is a different story, but they certainly can and do occur.
So to answer the original question, I'd aim for a midrange trough and call it a day. That way you don't have to worry about people freaking out about red values in the EMR or the dreaded <10 trough.
