Controlled substances are drugs which have a potential for abuse. They are classified by the U.S. Controlled Substances Act of 1970 and the individual state laws into five schedules according to three basic considerations:

1. the degree of potential for abuse;

2. whether the substance has currently accepted medical use; and

3. whether the use under medical circumstances is considered safe⁽⁷⁾. The schedules are known as schedule I, II, III,  IV, V, schedule I being the most restrictive and V the least restrictive. Schedule I substances have no accepted medical uses and are illegal (heroin, LSD, marijuana); schedules II, III, IV, and V have accepted medical uses and generally have Food and Drug Administration (FDA) approval for medical use. Schedule II substances can be narcotic or non-narcotic. Schedule II narcotics include morphine, methadone, hydromorphone, and oxycodone.⁽⁸⁾