First of all, if you never tried a trial run with lasix do not use them, they are dangerous and can kill you. A trial run usually a month before your show can give you an idea of what your body can handle and how you feel, it hits hard once it hits the blood stream, I mean real hard, like a full bladder within minutes of taking them.
Lasix is disaster for 95% of bodybuilders, just the way it is, however it works for me to a T, like bang on everytime. a few pointers with lasix.
The day before carbing drink as much as humanly possible, I mean enormous amounts, then when you start carbing for the first day do not use the lasix, on the second day of carbing then use lasix as needed, can be twice a day the day before and once in the morning the day of, assuming this is a thursday loading protocol.
Now people always say how they go flat with lasix, which is why I drink as much as I can before the loading phase, so the carbs suck all the water into the muscle and when the lasix does its job there is still water left within the muscle and the water under the skin is gone.
Not a good idea to use it if you are not experienced though, not what you want to hear but you know