There are quite a few underlying diseases and several drugs involved here.
Nevertheless, your question may not have anything to with them!?
Generally both urea and creatinine
rise together (eg. renal impairment)
At times urea rises disproportionately (eg. Dehydration
Raising creatinine with normal urea is rather unusual -
It could mean technical error - repeat it
If it is still the same, one need to investigate for metabolic / muscle disease