I use 10%. I also do more like 5ml each time. I do cough a ton, but that's the point. I emailed the UNC investigator after the initial US study, and asked him about how 7% was selected, and about using 10%. Here was his response:
Regarding the concentration that was studied, 7% was a compromise between a dose that was most effective and what is well tolerated (in short term studies of mucociliary clearance - where 0.9%, 3%, 7%, and 12% were tested - 7% and 12% were similar, and better than 0.9 and 3%, but 12% wasn't well tolerated). Therefore, if concentrations higher than 7% are well tolerated in an individual, we have often gone up to 10% with further benefit (if you tolerate 7% easily, you probably will tolerate 10%, but obviously should do this in conjunction with your CF doctor). Your instinct to increase to 10% is probably a good one, therefore...
It also saves me half of the copay - my insurance considers 10% and 3% two difference prescriptions.
Chris
26 m w/CF