(2)(A) In accordance with rules adopted by the board and the committee, a collaborating physician may delegate to a physician assistant working in collaboration with the physician the authority to prescribe and/or issue legend drugs and controlled substances listed in Schedules II, III, IV, and V of title 39, chapter 17, part 4. The rules adopted prior to March 19, 1999, by the board and the committee governing the prescribing of legend drugs by physician assistants shall remain effective after March 19, 1999, and may be revised from time to time as deemed appropriate by the board and the committee. The board and the committee may adopt additional rules governing the prescribing of controlled substances by physician assistants. A physician assistant to whom is delegated the authority to prescribe and/or issue controlled substances must register and comply with all applicable requirements of the drug enforcement administration; see full law