the only thing that I can see to fit your limited facts is Fl Stat 893.0356 which is the control of a controlled substance analog. This is a substance designed to mimic the effects of a controlled substance and may apply to your facts if the substance was tested and found not to be oxycodone but a counterfiet mimicing its effects and are treated as a schedule 1 drug
Apparently, the term "legend drug" can refer to any prescription medication. In the State of Washington, RCW 69.41.010 (12) defines "Legend drugs" as meaning any drugs which are required by state law or regulation of the state board of pharmacy to be dispensed on prescription only or are restricted to use by practitioners only. There are, of course, federal statutes defining "controlled substances" which include prescription medications.