The United States Government developed the Federal Comprehensive Drug Abuse Prevention and Control Act (Controlled Substances Act) in 1970. One of the primary purposes of the act was to improve the development, distribution, and allocation of controlled medications. The Controlled Substances Act categorizes certain medications into five different schedules based on misuse potential. Schedule I medications have the highest misuse potential; schedule V medications have the lowest misuse potential.[1]

As many states in the USA have now passed laws that decriminalize marijuana, this does not change the federal decision of marijuana as a schedule I drug. There is a collaboration between the US Attorney General and the Department of Health and Human Services to determine the hierarchy of schedule for a medication.[1][2]

There has been a recent discussion on controlled substance policy, with the current state of the opioid epidemic in the United States. One implication to combat the overuse of opioids has been by the Centers for Medicare and Medicaid Services (CMS), which uses an Over-utilization Monitoring System (OMS) which is part of the Medicare Part D, to help identify patients at risk for substance use disorder. Another initiative has been to implement national registries that would indicate controlled substance allocation by a patient search.[3][4]

Schedule I medications have very high misuse potential and are considered to have no FDA (Food and Drug Administration) approved medical use. These medications are prohibited from being prescribed or distributed. Examples of schedule I drugs are heroin, ecstasy (MDMA), lysergic acid diethylamide (LSD), marijuana, and gamma-hydroxybutyric acid (GHB).[1] 

Schedule II drugs have a high misuse potential with or without known dependence to develop, yet these medications have accepted clinician use. Examples of schedule II drugs are cocaine, morphine, codeine, hydromorphone, methadone, and fentanyl.[1]

Schedule III pharmaceuticals are considered to have an intermediate level of misuse potential. Drugs in this classification include anabolic steroids and ketamine.[1]

Schedule IV medications are considered to have some misuse potential but are less of a risk than Schedule III drugs. Examples of such are clonazepam, diazepam, midazolam, phenobarbital, and tramadol.[1]

Schedule V drugs have the lowest potential for misuse and development of use disorder; examples of such are pregabalin, diphenoxylate/atropine, and promethazine.[1]

Only registered practitioners with the Drug Enforcement Agency (DEA) are permitted to prescribe controlled substances. All prescriptions for schedule II medications must be given to the pharmacist in a written form or transmitted by an approved computer system for EPCS (electronic prescribing of controlled substances). In fact, a number of states now require EPCS systems to be used for controlled substance prescribing. A prescription for a schedule II medication may be called in by a registered practitioner in an emergency situation; however, a written prescription must follow up within 7 days.[5]

The healthcare team, e.g., physicians, nurses, pharmacists, etc., need to work together to address pain control in their patients accurately as in the case of opioid analgesics which is a common class of controlled substances.  The healthcare team should schedule their patients for routine follow-up visits that include a history and physical exam to monitor for adverse drug effects and drug misuse. Monitoring for signs of drug misuse is a very important responsibility for the healthcare team because of the epidemic rates of drug misuse worldwide, e.g., the USA, which can lead to death because of respiratory depression, e.g., opioid analgesics. Methods for monitoring drug abuse as well as drug diversion include the following examples: assessment surveys, state prescription drug monitoring programs, urine screening, adherence check-lists, motivational counseling, and dosage form, e.g., tablet counting. [Level V]