approved by the Food and Drug Administration for the treatment of substance use disorder. (iii) Definitions In this subparagraph: (I) Prior authorization The term prior authorization means the process by which a health insurance issuer or pharmacy benefit management company determines the medical necessity of otherwise covered health care services prior to the rendering of such health care services. Such term includes any health insurance issuer’s or utilization review entity’s requirement that a subscriber or health care provider notify the issuer or entity prior to providing a health care service. (II) Step therapy The term step therapy means a protocol or program that establishes the specific sequence in which prescription drugs for a medical condition that are medically appropriate for a particular patient are authorized by a health insurance issuer or prescription drug management company. (3) Amount of grant to tribal governments (A) Indian tribes In this section, the term Indian tribe has the meaning given such term in section 4 of the Indian Self-Determination and Education Assistance Act. (B) Formula grants The Secretary, acting through the Indian Health Service, shall use 10 percent of the amount available under section 3415 for each fiscal year to provide formula grants to Indian tribes in an amount determined pursuant to a formula and eligibility criteria developed by the Secretary in consultation with Indian tribes, for the purposes of addressing substance use. (C) Use of amounts Notwithstanding any requirements in this section, an Indian tribe may use amounts provided under grants awarded under this paragraph for the uses identified in subsection (b) and any other activities determined appropriate by the Secretary, in consultation with Indian tribes. (b) Use of amounts (1) In general A State or tribe may use amounts provided under grants awarded under section 3411 for— (A) prevention services described in paragraph (3)