Note: it is discouraged to use caffeine while on creatine; while creatine makes your muscles hold water, caffeine will do the opposite, thereby reducing the effects of the creatine intake.
I suggest you take a look at this site about Creatine.
Here’s a quote regarding mixing Creatine and Juice
“Don’t mix creatine with citrus juice. Orange, grapefruit, cranberry, in fact, most fruit juices have been most recently found to neutralize the activity of creatine monohydrate. The reason is the waste product creatinine develops. A lot of you put creatine on your tongue and drink it down with grapefruit juice. If you have taken creatine this way in the past, stop it now! You are not getting creatine, you’re getting waste product.”
Also, Muscle cramps and pulls are common side effects of creatine usage. However, this is due mainly to dehydration on the users part. Since we all know that creatine pulls water into the muscles from the core, if there isn’t enough water in the persons core, they often cramp. This is why it’s also recommended not to drink much alcohol, caffeine or other dehydrating agents while cycling creatine.
References for these comments are posted on the bottom of that webpage.