I ran this by my hubbie because he is the sport supplement person in our household (his dad owns a health food/sport supplement store in WA) and worked for his dad for about 10 years. Here's what he had to say about it.
Creatine is a cell volumizer which means that it is sucking water into the muscle cell and creating ATP (a source of energy). CFers should be drinking more water than the "average" person anyways, but it is essential when using creatine because it is using up more water to fulfill it's purpose. So yes, more water is very very necessary.
Just some FYI's...
Creatine is most beneficial when used before and after workouts. Before it is used to increase energy for a work out and after a workout it is sucked into the muscle, therefore increasing the muscle mass.
If you are doing any type of heavy cardio (long distance running or biking) it is not recommended for use because it draws so much water out of the body and into the muscle that it causes cramping (due to lack of water and inability to replenish it at a rate satisfactory to the body)
Most creatine bottles they suggest using a "loading phase" which is not really necessary. It is only necessary to take 10 grams of creatine in a day.
Julie (wife to Mark 24 w/CF)