i am getting a lot of dandruff /dry skin coming off my scalp. what is causing this? and will it go away with time?

i am using proscar, rogaine, and nizoral 2percent

what is the purpose of the nizoral shampoo? just to stop the irritation from minoxdil or does it have some other purpose?

i am guessing that the shampoo is getting rid of layers of my skin so that the rogaine can absorb...so in a couple of months i am guessing the dandruff will stop?

or is this because i am not using enough of a regular shampoo and therefore am getting dandruff?

im just confused because the nizoral shampoo is Rx antidandruff