Why Is 'benforce-m' Prescribed For Irregular Menstrual Periods?

Iam 28yrs old ummaried . i have irrugular periods. so doctor advised me krimson-35 for 6months. during this 6 months wen i used those tablets i got regular periods. after 6months doctor asked me to consult. and she asked me to stop krimson 35 tablet. and start having benforce-m tablet. im worried. wht is this benforce-m tablet :( ,what is the connection?