Coupons from drug company

Is it allowed by blue cross of oklahoma for me to use a coupon from a drug manufacturer that is meant to be used at the pharmacy for people with health insurance?Thier website says its okay to use for people who purchased insurance from the federal marketplace. I am wondering since I have a bcbsok plan purchased through the federal website and I get premium assistance and cost sharing assistance from the federal government based on income.And i wasnt sure if blue cross allows it.