Definition
A Schedule III controlled substance is a drug that the United States Drug Enforcement Administration (DEA) has classified as having a moderate to low potential for physical and psychological dependence. Ketamine has been classified as Schedule III since 1999, placing it in the same regulatory category as drugs such as testosterone, anabolic steroids, and certain combination products containing codeine. This classification carries specific legal requirements for prescribing, dispensing, record-keeping, and storage.
The Controlled Substances Act
The Controlled Substances Act (CSA), enacted in 1970, established five schedules (I through V) for classifying drugs based on three criteria: accepted medical use, potential for abuse, and likelihood of causing dependence. The schedules range from Schedule I (highest restriction, no accepted medical use — such as heroin and MDMA) to Schedule V (lowest restriction, limited abuse potential — such as certain cough preparations containing small amounts of codeine).
Schedule III substances are defined as drugs that:
- Have a currently accepted medical use in the United States
- Have a potential for abuse that is less than Schedule I and II substances
- May lead to moderate or low physical dependence or high psychological dependence if abused
What Schedule III Means for Ketamine Prescribing
Ketamine's Schedule III status carries several practical implications for patients and providers:
Prescribing authority: Any practitioner with a valid DEA registration and state prescribing license can prescribe ketamine. This includes physicians (MDs and DOs), and in many states, nurse practitioners and physician assistants with appropriate authority. Unlike Schedule II drugs, Schedule III prescriptions may include refills — up to five refills within six months from the date of issue.
Prescription requirements: Schedule III prescriptions can be transmitted electronically, by phone, by fax, or on paper. They do not require the triplicate paper forms or tamper-resistant prescription pads that some states mandate for Schedule II substances. However, all Schedule III prescriptions must include the prescriber's DEA number and comply with state-specific regulations.
Record-keeping: Pharmacies and prescribers must maintain detailed records of all ketamine prescriptions dispensed, including quantities, dates, and patient information. These records are subject to DEA inspection. Inventories of Schedule III substances must be conducted every two years.
Storage and security: Pharmacies and clinics that stock ketamine must store it in a securely locked cabinet or area with limited access. While the security requirements are less stringent than for Schedule II drugs (which require a safe or vault in some settings), they are still more rigorous than for uncontrolled medications.
Telehealth Considerations
Ketamine's status as a controlled substance has significant implications for telehealth prescribing. Under the Ryan Haight Online Pharmacy Consumer Protection Act of 2008, controlled substances generally require an in-person medical evaluation before they can be prescribed via telemedicine. Temporary flexibilities introduced during the COVID-19 public health emergency allowed some exceptions, and the DEA has continued to update telehealth prescribing rules as of 2025.
For details on the evolving federal rules, see our article on DEA telehealth prescribing changes. These regulations are particularly relevant for at-home ketamine programs, where patients receive oral or sublingual formulations prescribed through telehealth consultations and dispensed by compounding pharmacies. Providers and patients must comply with both federal DEA rules and applicable state regulations governing controlled substance prescribing.
Comparison to Other Schedules
Understanding where Schedule III sits in the broader framework provides useful context:
- Schedule I: No accepted medical use, high abuse potential (heroin, LSD, psilocybin — though some are under reclassification review)
- Schedule II: High abuse potential with accepted medical use, severe dependence risk (oxycodone, fentanyl, amphetamines, cocaine for medical use)
- Schedule III: Moderate abuse potential, accepted medical use (ketamine, testosterone, buprenorphine)
- Schedule IV: Lower abuse potential (benzodiazepines, zolpidem)
- Schedule V: Lowest abuse potential among controlled substances (pregabalin, certain low-dose codeine preparations)
Ketamine's Schedule III placement reflects its recognized therapeutic value alongside its documented potential for misuse, particularly in recreational settings.
References
- DEA Drug Scheduling Overview — Official DEA resource explaining the controlled substances scheduling system.
- Controlled Substances Act, Title 21 USC — Full text of the federal law governing controlled substances.
- Ryan Haight Act and Telehealth Prescribing — The federal law governing online prescribing of controlled substances.
- NIMH Ketamine Overview — National Institute of Mental Health resource on psychiatric medications.
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