Michigan Compiled Laws, Chapter 550. General Insurance Laws § 550.1401h

(a) Provide for participation of participating physicians, dentists, and pharmacists in the development of the formulary.

(b) Disclose to health care providers and upon request to members the nature of the formulary restrictions.

(c) Provide for exceptions from the formulary limitation when a nonformulary alternative is a medically necessary and appropriate alternative. This subdivision does not prevent a health care corporation from establishing prior authorization requirements or another process for consideration of coverage or higher cost-sharing for nonformulary alternatives. Notice as to whether or not an exception under this subdivision has been granted shall be given by the health care corporation within 24 hours after receiving all information necessary to determine whether the exception should be granted.