Controlled Substance

Key facts

Legal basis

Controlled Substances Act of 1970, 21 U.S.C. 801 and following

Enforced by

Drug Enforcement Administration (DEA)

Schedules listed at

21 CFR Part 1308

Number of schedules

Five, from Schedule I (most restricted) to Schedule V

Prescriber requirement

DEA registration, plus any state controlled substance license

What is a controlled substance?

The Controlled Substances Act (CSA) sorts substances into schedules based on accepted medical use, abuse potential and the likelihood of physical or psychological dependence. The Drug Enforcement Administration (DEA) administers the schedules, and the Department of Health and Human Services, through the FDA, provides the scientific and medical evaluation that informs scheduling decisions.

Controlled status applies on top of FDA approval. An approved prescription drug such as oxycodone is both an FDA-regulated drug and a Schedule II controlled substance, and states can add their own, sometimes stricter, controls.

The five controlled substance schedules

Marijuana has long been listed in Schedule I under federal law. The DEA proposed moving it to Schedule III in 2024, and a December 2025 executive order directed the government to expedite that rescheduling. The process has been contested, so check the current DEA schedule before relying on either listing.

Schedules run from most to least restricted, and the examples below are common but not exhaustive:

• Schedule I: high abuse potential and no currently accepted medical use in the United States, such as heroin and LSD.
• Schedule II: high abuse potential with accepted medical use, such as fentanyl, oxycodone, amphetamine and methylphenidate. Prescriptions cannot be refilled.
• Schedule III: lower abuse potential than Schedules I and II, such as ketamine, anabolic steroids and buprenorphine products.
• Schedule IV: lower abuse potential than Schedule III, such as alprazolam, diazepam and tramadol.
• Schedule V: the lowest abuse potential, such as pregabalin and cough preparations with limited amounts of codeine.

Why controlled substance status matters

Scheduling affects who can prescribe, how drugs are supplied and what data exist:

• Prescriber oversight: prescribing requires a DEA registration, and state prescription drug monitoring programs (PDMPs) track dispensing of controlled drugs.
• Prescribing rules: electronic prescribing is required for most controlled substance prescriptions under Medicare Part D, with exceptions, and telemedicine prescribing without an in-person visit has depended on temporary DEA extensions since the COVID-19 public health emergency.
• Supply constraints: the DEA sets annual aggregate production quotas for Schedule I and II substances, which have been cited as a factor in shortages of stimulants used for ADHD.
• Data joins: the NDC Directory records a DEA schedule for listed products, so analysts can flag controlled products in pricing, recall and shortage data.