Does Primulet N Tablets Delay The Periods?

My period is due on the 3rd March 2014 but i have an important engagement to attend that day and i want to hold back my period for 2 days. My pharmacist recommended primolut n he said i should take it from the Friday which is the 28th March taking 3 tablets a day for 7 days and i should be fine. Would this tablet really hold up my period? I'm sooo worried