This sort of goes in my “duh” file...stimulant drinks can cause the kidneys to flush out extra fluid. Dehydration produces increased risk of blood clots. Drink your Red Bull, and then a bottle of water, and I would expect it would be less of a problem.
Use the pee test. If your pee is dark, you're dehydrated. So drink more liquids. Try to maintain pee that is almost clear with an amber tint.