Thank You for Your reply strawberrycoff

The problem is, that I am 3 hours away from the lab. And it's at least 40 degrees (in celcius) here. I 'm just scared that the substitute will break down faster than 8 hours.

The diuretic pill's label is DESAL, and it contains FUROSEMIDE.
I am not %100 sure but maybe it would help me to give a clean pee w/o any THC-COOH in it. Do You think I have no chance with this pills ?