Which drug is placed in Schedule II (C-II), the schedule with an accepted medical use but the highest abuse potential of any prescribable controlled substance?

Explanation

Hydromorphone is a C-II opioid; other common C-II agents include oxycodone, fentanyl, methylphenidate, and amphetamine. Alprazolam is C-IV, pregabalin is C-V, and ketamine is C-III, so all three carry a lower federally assigned abuse potential. Schedule II drugs have accepted medical use but the greatest abuse and dependence risk among drugs that may still be prescribed.