Is It Safe To Take Floral For Inconsistency In Passing Urine During Sleep?

I am 55, doctor advised to take flotral 10 mgs daily. How long i have to take ? I have the problem of passing unine at night when the bladder seems to be full. IT gradually releases the little pain and takes time to complete. At day time there is no such major problem. on USG of lower abdoman nothing observed abnormal on little residual of urine content in the bladder. please suggest.