(2) As used in this subsection: (A) The term “date rape drug” means— (i) gamma hydroxybutyric acid (GHB) or any controlled substance analogue of GHB, including gamma butyrolactone (GBL) or 1,4–butanediol; (ii) ketamine; (iii) flunitrazepam; or (iv) any substance which the Attorney General designates, pursuant to the rulemaking procedures prescribed by section 553 of title 5 , to be used in committing rape or sexual assault. The Attorney General is authorized to remove any substance from the list of date rape drugs pursuant to the same rulemaking authority. (B) The term “authorized purchaser” means any of the following persons, provided such person has acquired the controlled substance in accordance with this chapter: (i) A person with a valid prescription that is issued for a legitimate medical purpose in the usual course of professional practice that is based upon a qualifying medical relationship by a practitioner registered by the Attorney General. A “qualifying medical relationship” means a medical relationship that exists when the practitioner has conducted at least 1 medical evaluation with the authorized purchaser in the physical presence of the practitioner, without regard to whether portions of the evaluation are conducted by other heath professionals. The preceding sentence shall not be construed to imply that 1 medical evaluation demonstrates that a prescription has been issued for a legitimate medical purpose within the usual course of professional practice. (ii) Any practitioner or other registrant who is otherwise authorized by their registration to dispense, procure, purchase, manufacture, transfer, distribute, import, or export the substance under this chapter. (iii) A person or entity providing documentation that establishes the name, address, and business of the person or entity and which provides a legitimate purpose for using any “date rape drug” for which a prescription is not required.