yes, you can.
creatine isnt magic. your not going to see crazy results. maybe 1 or 2 more reps and a bit harder muscles. nothing dramatic.
creatine is converted to creatinine and excreted through the urine. high concentrations of creatinine can be painful to piss out. think of when you mix creatine with water, it doesnt dissolve very well. creatinine in high concentrations does the same in your body. your pissing out undissolved solids and thats making micro-tears in your urethra.
your probably also very dehydrated, making urine volume lower, increasing the concentration even more.
5grams/day tops, and cycling is a good idea too^^^^^^^