Mefenamic Acid

[queenofmean]

I was told that I should aim to take this 2 days prior to my period starting. I never had a good cycle before it varied quite a bit. Last time I came off the pill I fell into a normal cycle this time it seems variable. So should I aim to start taking this as normal (assuming I start on date due) or should I wait until I actually start. A little bamboozled to say the least.
TIA