controlled substance schedule

In the United States, drugs and the chemicals used to make them are sorted into five categories, called schedules, according to two things: whether the drug has an accepted medical use, and how likely it is to be abused or to cause dependence. The Drug Enforcement Administration maintains the list.

Schedule I is for substances the agency considers to have no currently accepted medical use and a high potential for abuse, heroin and LSD among them. Schedule II covers drugs with a high abuse potential that are nonetheless used in medicine, including cocaine, methadone and oxycodone. The potential for abuse falls as the numbers rise, and Schedule V represents the least.

The schedule is not a safety rating so much as a set of controls. It governs how a drug is prescribed, how it is stored, how repeat supplies work and what records a pharmacy has to keep. It also has a practical consequence for new medicines: a drug the FDA has approved but the DEA has not yet scheduled cannot go on sale until that review is finished, so approval and availability can be months apart.