Is Ponstan 250mg Prescribed For Treating Excessive Menstrual Bleeding?

Hello,　I'm causing irregular periods. It has been since one month ago.I'm still in my periods. The amount is small,but i have to change pads twice a day. Today a doctor prescribed ponstan 250mg. I knew ponstan is for pain killer medication when i got home.
Is it effective to stop bleeding? I have no pain.
Could you please give me some advice?