(a) In this section, “drug formulary” means a list of drugs preferred for use and eligible for coverage by a health coverage plan.
(b) A health coverage plan provided under this chapter that uses a drug formulary in providing a prescription drug benefit must require prior authorization for coverage of the following categories of prescribed drugs if the specific drug prescribed is not included in the formulary:
(1) a gastrointestinal drug;
(2) a cholesterol-lowering drug;
(3) an anti-inflammatory drug;
(4) an antihistamine drug; and
(5) an antidepressant drug.

(c) Every 12 months the trustee shall submit to the comptroller and the Legislative Budget Board a report regarding any cost savings achieved in the program through implementation of the prior authorization requirement of this section. The report must cover the previous 12-month period.
(d) In the report under Subsection (c), the trustee:
(1) may include any cost savings achieved in the program for coverage of prescribed drugs that are not included in the categories listed in Subsection (b) for which prior authorization is required by a health coverage plan provided under this chapter; and
(2) considering cost and medical necessity, shall identify any categories of prescribed drugs in addition to the categories listed in Subsection (b) for which requiring prior authorization could achieve cost savings.