Suggest Atment For Itchy Scalp

I am a 70-year old male but what I describe is not new. I shampoo daily with a selenium sulfide shampoo. Six hours later my scalp is very oily and itchy. I can pick up the oil visibly on a Kleenex. The only solution I have found to date is to wash my hair again with some kind of soap and water. I have a fast way to do this at a sink but I wish there were something else I could do so I could at least go a day between shampoos. My skin is naturally oily to begin with, but the top of my head (where it is mostly bald) is over the top. Any suggestions? Additional information: 5'-6"; 173 lbs; Caucasian; taking aspirin, fenofibrate, atenolol, and 4 grams fish oil daily, but the oily itchy scalp predates all of those and has not varied as those meds were added and changed. No skin diseases or history thereof.