Hi, can Primolut N stop a period once it has just started. I m wary of taking the tablets in case of side effects, especially if i dont need to. My wedding is in 6 days though, and there s a strong chance i could have my period ony wedding which would be a nightmare. My period is due either tomorrow or the next day, but i have strong period pain right now and sometimes it does come early. If it comes today or tomorrow I ll be fine by Saturday, but if I risk not taking the tablets it might come of Wednesday which will too late (apparently you need to rstart taking tablets 3 days prior). My GP told me to take on the first day of my period, but packet and websites say 3 days before so I don t know what to do.