Hello, I Have Just Began My Monthly Menses But Would

Hello,

I have just began my monthly menses but would like to stop the flow due to unavoidable activities tomorrow and day after. My local Chemist had given me Primolut N. Will it stop the flow and if yes, when and what are the side effects if any? Also, Should the flow stop, when can I expect them again?

Thank you.

Regards,