SUPPLEMENTARY INFORMATION:

The Drug Enforcement Administration (DEA) issues a temporary scheduling order ^[1] (in the form of a temporary amendment) to add 2-(2-fluorophenyl)-2- ( printed page 30205) (methylamino)cyclohexan-1-one (commonly known as 2-fluorodeschloroketamine or 2-FDCK), including its salts, isomers, and salts of isomers whenever the existence of such salts, isomers, and salts of isomers is possible, to schedule I under the Controlled Substances Act (CSA).

Legal Authority

The CSA provides the Attorney General with the authority to temporarily place a substance in schedule I of the CSA for two years without regard to the evaluation requirements of 21 U.S.C. 811(b), if he finds that such action is necessary to avoid an imminent hazard to the public safety.^[2] In addition, if proceedings to control a substance are initiated under 21 U.S.C. 811(a)(1) while the substance is temporarily controlled under section 811(h), the Attorney General may extend the temporary scheduling for up to one year.^[3]

Where the necessary findings are made, a substance may be temporarily scheduled if it is not listed in any other schedule under 21 U.S.C. 812, or if there is no exemption or approval in effect for the substance under section 505 of the Federal Food, Drug, and Cosmetic Act (FD&C Act), 21 U.S.C. 355.^[4]

In addition, the United States is a party to the 1971 United Nations Convention on Psychotropic Substances (1971 Convention), Feb. 21, 1971, 32 U.S.T. 543, 1019 U.N.T.S. 175, as amended. Procedures respecting changes in drug schedules under the 1971 Convention are set forth in 21 U.S.C. 811(d)(2)-(4). When the United States receives notification of a scheduling decision pursuant to Article 2 of the 1971 Convention indicating that a drug or other substance has been added to a schedule specified in the notification, the Secretary of the Department of Health and Human Services (HHS), after consultation with the Attorney General, shall first determine whether existing legal controls under subchapter I of the CSA and the FD&C Act meet the requirements of the schedule specified in the notification with respect to the specific drug or substance. In the event that the Secretary did not consult with the Attorney General, and the Attorney General did not issue a temporary order, as provided under 21 U.S.C. 811(d)(4), the procedures for permanent scheduling set forth in 21 U.S.C. 811(a) and (b) control. The Attorney General has delegated scheduling authority under 21 U.S.C. 811 to the Administrator of DEA (Administrator).^[5]

Background

On June 6, 2024, the Secretariat of the United Nations advised the Secretary of State of the United States that the Commission on Narcotic Drugs (CND), during its 67th session on March 19, 2024, voted to place 2-fluorodeschloroketamine in Schedule II of the Convention on Psychotropic Substances of 1971 (CND Decision 67/4). As a signatory to this international treaty, the United States is required to place appropriate controls within the CSA on 2-fluorodeschloroketamine to meet the requirements of the treaty. To meet the minimum requirements of this treaty and to confront these emerging substances, DEA is temporarily placing 2-fluorodeschloroketamine in schedule I of the CSA.

The CSA requires the Administrator to notify the Secretary of HHS of an intent to temporarily place a substance in schedule I of the CSA ( i.e., to issue a temporary scheduling order).^[6] By letter dated November 1, 2024 (the November 1 DEA letter), the previous Administrator transmitted the required notice to place 2-fluorodeschloroketamine in schedule I on a temporary basis to the then-Assistant Secretary for Health of HHS (Assistant Secretary).^[7] By letter dated November 8, 2024 (the November 8 HHS letter), the previous Assistant Secretary responded to this notice and advised DEA that, based on a review by the Food and Drug Administration (FDA), there were currently no investigational new drug applications (IND) or approved new drug applications (NDA) for 2-fluorodeschloroketamine. The previous Assistant Secretary also stated that HHS had no objection to the temporary placement of this substance in schedule I of the CSA. However, DEA requested an updated response from HHS by letter dated May 28, 2025 (the May 28 DEA letter), due to the change in HHS's leadership after the November 8 HHS letter. By letter dated June 11, 2025 (the June 11 HHS letter), the then-Acting Assistant Secretary of HHS responded that, based on an updated review by FDA, there were currently no NDAs or INDs for 2-fluorodeschloroketamine. Therefore, HHS had no objections to the temporary placement of 2-fluorodeschloroketamine in schedule I. 2-Fluorodeschloroketamine is not currently listed in any schedule under the CSA, and no exemptions or approvals under 21 U.S.C. 355, are in effect for this substance.

DEA has taken into consideration the then-Acting Assistant Secretary's comments as required by 21 U.S.C. 811(h)(4). DEA has found the control of 2-fluorodeschloroketamine in schedule I on a temporary basis is necessary to avoid an imminent hazard to public safety.

As required by 21 U.S.C. 811(h)(1)(A), DEA published a notice of intent (NOI) to temporarily schedule 2-fluorodeschloroketamine in the Federal Register on January 20, 2026.^[8] That NOI discussed findings from DEA's three-factor analysis dated January 2026, which DEA made available on www.regulations.gov.

To find that temporarily placing a substance in schedule I of the CSA is necessary to avoid an imminent hazard to public safety, the Administrator must consider three of the eight factors set forth in 21 U.S.C. 811(c): the substance's history and current pattern of abuse; the scope, duration, and significance of abuse; and what, if any, risk there is to public health.^[9] Consideration of these factors includes any information indicating actual abuse, diversion from legitimate channels, and clandestine importation, manufacture, or distribution of this substance.^[10]

Substances meeting the statutory requirements for temporary scheduling may only be placed in schedule I.^[11] Substances in schedule I have high potential for abuse, no currently accepted medical use in treatment in the United States, and a lack of accepted safety for use under medical supervision.^[12]

2-Fluorodeschloroketamine

The availability of new psychoactive substances on the illicit drug market continues to pose an imminent hazard to public safety. Adverse health effects associated with the abuse of such substances and their increased popularity have become a serious concern in recent years. Such substances include 2-fluorodeschloroketamine, which has been identified on the illicit drug ( printed page 30206) market in the United States and worldwide.

The positive identification of 2-fluorodeschloroketamine in law enforcement seizures and toxicology reports poses a serious concern to public safety. 2-Fluorodeschloroketamine has been detected in 61 drug seizures across 12 states since 2018, and this substance has been detected in biological samples from 3 overdose cases in the United States.

Data obtained from preclinical pharmacology studies show that 2-fluorodeschloroketamine has a pharmacological profile similar to that of other arylcyclohexylamines, such as phencyclidine (PCP) and ketamine, which are schedule II and III controlled substances, respectively. Due to these pharmacological similarities, the use of 2-fluorodeschloroketamine presents a high risk of abuse and may negatively affect users and their communities. These pharmacological similarities also lead to similar clinical presentations of intoxication that range from hallucinogenic-like adverse effects to death. Thus, 2-fluorodeschloroketamine poses an imminent hazard to public safety.

Available data and information for 2-fluorodeschloroketamine, summarized below, indicate that this substance has a high potential for abuse, no currently accepted medical use in treatment in the United States, and a lack of accepted safety for use under medical supervision.^[13] DEA's three-factor analysis is available in its entirety under “Supporting and Related Material” of the public docket for this action at www.regulations.gov under Docket Number DEA-1442.

Factor 4. History and Current Pattern of Abuse

2-Fluorodeschloroketamine belongs to a chemical structural class of substances known as arylcyclohexylamines that includes dissociative anesthetics PCP (a schedule II substance) and ketamine (a schedule III substance). Details on 2-fluorodeschloroketamine synthesis have been available since 2014, long after its first reported synthesis without details in 1987. In 2015, online forum users began to discuss the psychoactive properties of 2-fluorodeschloroketamine and commonly compared 2-fluorodeschloroketamine to ketamine. Unlike ketamine, however, 2-fluorodeschloroketamine has no currently approved medical use. In the November 8 HHS letter to DEA, the then-Assistant Secretary stated that there were no FDA-approved NDAs or INDs for 2-fluorodeschloroketamine. In the June 11 HHS letter to DEA, the then-Acting Assistant Secretary reaffirmed that there were no FDA-approved NDAs or INDs for 2-fluorodeschloroketamine.

2-Fluorodeschloroketamine emerged on the illicit drug market similarly to other dissociative anesthetics that are trafficked for their psychoactive effects; this is evidenced by the identification of this substance in forensic drug exhibits and toxicology samples. Based on available data from user reports and law enforcement seizures, individuals typically purchase 2-fluorodeschloroketamine as powder or crystals, which are then crushed and placed into capsules or solubilized. Common routes of administration include oral consumption or insufflation, while less commonly mentioned routes include intramuscular injection, sublingual administration, and rectal insertion. In addition, scientific literature and toxicological reports indicate that 2-fluorodeschloroketamine is likely co-ingested with other substances, whether as separate products or a single product containing multiple licit and illicit substances. In toxicological reports, substances co-identified with 2-fluorodeschloroketamine included, but were not limited to, 2-fluoromethamphetamine (schedule I); 3,4-methylenedioxyamphetamine (MDA; schedule I); 3,4-methylenedioxymethamphetamine (MDMA; schedule I); 4-methoxy PCP; ADB-BUTINACA (schedule I); ketamine (schedule III); fentanyl (schedule II); mitragynine; morphine (schedule II); and various prescription drugs.

Factor 5. Scope, Duration and Significance of Abuse

Users on online forums began to discuss 2-fluorodeschloroketamine and its consumption in 2015. In 2016, government authorities in Spain first documented the appearance of 2-fluorodeschloroketamine on the illicit drug market, and this substance has since been detected in numerous countries, such as Australia, Austria, Canada, China, Denmark, Finland, France, Italy, the Netherlands, the United Kingdom, and the United States. Some of these countries actively regulated 2-fluorodeschloroketamine under psychoactive drug control regulations prior to its international control in 2024.

Law enforcement data indicate that the presence of 2-fluorodeschloroketamine is widespread in the United States. Since 2018, DEA's National Forensic Laboratory Information System (NFLIS-Drug) ^[14] registered a total of 61 reports, across 12 states, pertaining to the trafficking, ( printed page 30207) distribution, and abuse of 2-fluorodeschloroketamine.^[15] These states include California, Connecticut, Florida, Illinois, Louisiana, Michigan, New Jersey, New York, Ohio, Pennsylvania, Virginia, and West Virginia.

Factor 6. What, if Any, Risk There Is to Public Health

2-Fluorodeschloroketamine is a potent arylcyclohexylamine, and evidence suggests that users abuse this substance for its dissociative effects. Literature and case reports indicate that the clinical presentation of 2-fluorodeschloroketamine intoxication is similar to that from other arylcyclohexylamines, such as PCP (schedule II) and ketamine (schedule III), and ranges from hallucinogenic-like adverse effects to death. In nonfatal intoxications, adverse effects include acute neurological symptoms resulting in cognitive and behavioral abnormalities, as well as cardiovascular symptoms, such as hypertension and tachycardia. Literature also indicates that 2-fluorodeschloroketamine has been used as a “date rape” drug and was detected among 11 cases of drug-facilitated sexual assault internationally.

In addition, according to findings by the DEA Toxicology Testing Program (DEA TOX),^[16] 2-fluorodeschloroketamine has been positively identified in a total of three polysubstance overdose cases, two of which were fatal, and included both male (n = 2, both age 31) and female (n = 1, age 36) users. While toxicological and forensic case reports are available in medical and scientific literature and provide evidence of 2-fluorodeschloroketamine abuse, commonly used drug screening methods may not yet be able to identify 2-fluorodeschloroketamine. Consequently, additional emergency room admissions and fatalities involving 2-fluorodeschloroketamine have potentially occurred without report.

Lastly, U.S. law enforcement data indicate that 2-fluorodeschloroketamine has been encountered since 2018 and that this substance is easily and affordably obtainable online and on the illicit market. Due to the unknown purity and composition of drugs purchased online or on the illicit market, individuals may be unknowingly exposed to this substance despite their intentions to consume other drugs, such as bucinnazine, ketamine, or methoxphenidine. Analytical testing of seized samples indicates single and combinations of substances, suggesting that 2-fluorodeschloroketamine may be frequently used as an adulterant or ketamine substitute. The unpredictable levels of adulterant or drug purity across samples may pose significant harm to public health.

Finding of Necessity of Schedule I Placement To Avoid Imminent Hazard to Public Safety

In accordance with 21 U.S.C. 811(h)(3), based on the available data and information summarized above, the uncontrolled manufacture, distribution, reverse distribution, importation, exportation, conduct of research and chemical analysis, possession, and abuse of 2-fluorodeschloroketamine pose an imminent hazard to public safety. 2-Fluorodeschloroketamine has not been approved by FDA and has not been lawfully marketed in the United States. DEA is not aware of any currently accepted medical uses for 2-fluorodeschloroketamine in the United States. A substance meeting the statutory requirements for temporary scheduling, found in 21 U.S.C. 811(h)(1), may only be placed in schedule I. Substances in schedule I must have a high potential for abuse, no currently accepted medical use in treatment in the United States, and a lack of accepted safety for use under medical supervision. Available data and information for 2-fluorodeschloroketamine indicate that this substance meets the three statutory criteria.

As required by 21 U.S.C. 811(h)(4), in the November 1 DEA letter, the then-Administrator notified the then-Assistant Secretary of DEA's intention to temporarily place 2-fluorodeschloroketamine in schedule I. HHS had no objection to the temporary placement of this substance in schedule I. However, due to the change in HHS's leadership after the November 8 HHS letter, DEA requested an updated response from HHS in the May 28 DEA letter. In the June 11 HHS letter, the then-Acting Assistant Secretary reaffirmed that HHS had no objection to the temporary placement of 2-fluorodeschloroketamine in schedule I. DEA subsequently published this NOI in the Federal Register on January 20, 2026.^[17]

Conclusion

In accordance with 21 U.S.C. 811(h)(1) and (3), the Administrator considered available data and information, herein set forth the grounds for his determination that it is necessary to temporarily schedule 2-fluorodeschloroketamine in schedule I of the CSA, and finds that placement of this substance in schedule I is necessary to avoid an imminent hazard to the public's safety.

The temporary placement of 2-fluorodeschloroketamine in schedule I of the CSA will take effect on the date the order is published in the Federal Register and will remain in effect for two years, with a possible extension of one year, pending completion of the regular (permanent) scheduling process.^[18]

The CSA sets forth specific criteria for scheduling drugs or other substances. Permanent scheduling actions in accordance with 21 U.S.C. 811(a) are subject to formal rulemaking procedures “on the record after opportunity for a hearing” conducted pursuant to the provisions of 5 U.S.C. 556 and 557.^[19] The permanent scheduling process of formal rulemaking affords interested parties appropriate process and the government any additional relevant information needed to make a determination. Final decisions that conclude the permanent scheduling process of formal rulemaking are subject to judicial review.^[20] Temporary scheduling orders are not subject to judicial review.^[21]

Requirements for Handling

Upon the effective date of this temporary order, 2-fluorodeschloroketamine will be subject to the regulatory controls and administrative, civil, and criminal sanctions applicable to the manufacture, distribution, reverse distribution, importation, exportation, possession of, and engagement in research and conduct of instructional activities or chemical analysis with, schedule I controlled substances, including but not limited to the following:

1. Registration. Any person who handles (possesses, manufactures, distributes, reverse distributes, imports, ( printed page 30208) exports, engages in research, or conducts instructional activities or chemical analysis with) or desires to handle, 2-fluorodeschloroketamine must be registered with DEA to conduct such activities, pursuant to 21 U.S.C. 822, 823, 957, and 958, and in accordance with 21 CFR parts 1301 and 1312, as of May 22, 2026. Any person who currently handles 2-fluorodeschloroketamine and is not registered with DEA to conduct research with a schedule I controlled substance must submit an application for registration and may not continue to handle 2-fluorodeschloroketamine as of May 22, 2026, unless DEA has approved that application for registration pursuant to 21 U.S.C. 822, 823, 957, and 958, and in accordance with 21 CFR parts 1301 and 1312.

Notwithstanding the foregoing, pursuant to 21 U.S.C. 822(h), if, on May 22, 2026, a person is conducting research on 2-fluorodeschloroketamine and is already registered to conduct research with another controlled substance in schedule I, the person may continue to conduct research on 2-fluorodeschloroketamine if they submit a completed application for registration or modification of existing registration, as applicable, to conduct research with 2-fluorodeschloroketamine not later than 90 calendar days after May 22, 2026. The person may continue to conduct such research until the person withdraws the application or the Administrator serves on the person an order to show cause proposing denial of the application pursuant to 21 U.S.C. 824(c) and in accordance with 21 CFR 1301.37. If the Administrator serves an order to show cause proposing denial of the application or modification, the person may not continue to conduct research with 2-fluorodeschloroketamine and may not receive or otherwise obtain additional 2-fluorodeschloroketamine. If an order to show cause is served and the person requests a hearing in accordance with 21 CFR 1301.37(d), the hearing shall be held in accordance with 21 CFR 1301.41-1301.46 on an expedited basis and not later than 45 calendar days after the request is made, except that the hearing may be held at a later time if so requested by the person. If the person sends a copy of the application to a manufacturer or distributor of 2-fluorodeschloroketamine, receipt of the copy by the manufacturer or distributor constitutes sufficient evidence that the person is authorized to receive 2-fluorodeschloroketamine pursuant to 21 U.S.C. 822(h)(4). Continuation of research under 21 U.S.C. 822(h) does not authorize any other handling ( e.g., distribution) of 2-fluorodeschloroketamine.

Retail sales of schedule I controlled substances to the general public are not allowed under the CSA. Possession of any quantity of 2-fluorodeschloroketamine in a manner not authorized by the CSA on or after May 22, 2026 is unlawful, and those in possession of any quantity of 2-fluorodeschloroketamine may be subject to prosecution pursuant to the CSA.

2. Disposal of Stocks. Any person who does not desire or is unable to obtain a schedule I registration to handle 2-fluorodeschloroketamine must surrender all currently held quantities of this substance.

3. Security. 2-Fluorodeschloroketamine is subject to schedule I security requirements and must be handled in accordance with 21 CFR 1301.71-1301.93, as of May 22, 2026.

4. Labeling and Packaging. All labels, labeling, and packaging for commercial containers of 2-fluorodeschloroketamine must comply with 21 U.S.C. 825 and 958(e) and 21 CFR part 1302. Current DEA registrants will have 30 calendar days from May 22, 2026 to comply with all labeling and packaging requirements.

5. Inventory. Every DEA registrant who possesses any quantity of 2-fluorodeschloroketamine on the effective date of this order must take an inventory of all stocks of this substance on hand pursuant to 21 U.S.C. 827 and 958, and in accordance with 21 CFR 1304.03, 1304.04, and 1304.11. Current DEA registrants will have 30 calendar days from the effective date of this order to comply with all inventory requirements. After the initial inventory, every DEA registrant must take an inventory of all controlled substances (including 2-fluorodeschloroketamine) on hand on a biennial basis pursuant to 21 U.S.C. 827 and 958 and in accordance with 21 CFR 1304.03, 1304.04, and 1304.11.

6. Records. All DEA registrants must maintain records with respect to 2-fluorodeschloroketamine pursuant to 21 U.S.C. 827 and 958(e) and in accordance with 21 CFR parts 1304, 1312, and 1317, and section 1307.11. Current DEA registrants authorized to handle 2-fluorodeschloroketamine shall have 30 calendar days from the effective date of this order to comply with all recordkeeping requirements.

7. Reports. All DEA registrants must submit reports with respect to 2-fluorodeschloroketamine pursuant to 21 U.S.C. 827 and in accordance with 21 CFR parts 1304, 1312, and 1317, and sections 1301.74(c) and 1301.76(b), as of May 22, 2026. Manufacturers and distributors must also submit reports regarding 2-fluorodeschloroketamine to the Automation of Reports and Consolidated Order System pursuant to 21 U.S.C. 827 and in accordance with 21 CFR parts 1304 and 1312.

8. Order Forms. All DEA registrants who distribute 2-fluorodeschloroketamine must comply with order form requirements pursuant to 21 U.S.C. 828 and in accordance with 21 CFR part 1305 as of May 22, 2026.

9. Importation and Exportation. All importation and exportation of 2-fluorodeschloroketamine must be in compliance with 21 U.S.C. 952, 953, 957, and 958, and in accordance with 21 CFR part 1312 as of May 22, 2026.

10. Quota. Only DEA-registered manufacturers may manufacture 2-fluorodeschloroketamine in accordance with a quota assigned pursuant to 21 U.S.C. 826 and in accordance with 21 CFR part 1303, as of May 22, 2026.

11. Liability. Any activity involving 2-fluorodeschloroketamine not authorized by or in violation of the CSA, occurring as of May 22, 2026, is unlawful, and may subject the person to administrative, civil, and/or criminal sanctions.

Regulatory Analyses

The CSA provides for expedited temporary scheduling actions where necessary to avoid an imminent hazard to public safety. Under 21 U.S.C. 811(h)(1), the Administrator, as delegated by the Attorney General, may, by order, temporarily place substances in schedule I. Such orders may not be issued before the expiration of 30 days from: (1) the publication of a notice in the Federal Register of the intent to issue such order and the grounds upon which such order is to be issued, and (2) the date that notice of the proposed temporary scheduling order is transmitted to the Assistant Secretary, as delegated by the Secretary of HHS.^[22]

Inasmuch as section 811(h) directs that temporary scheduling actions be issued by order (as distinct from a rule) and sets forth the procedures by which such orders are to be issued, DEA believes the notice-and-comment requirements of the Administrative Procedure Act (APA) at 5 U.S.C. 553, which are applicable to rulemaking, do not apply to this temporary scheduling order. The APA expressly differentiates between orders and rules, as it defines an “order” to mean a “final disposition, whether affirmative, negative, injunctive, or declaratory in form, of an agency in a matter other than rule ( printed page 30209) making.”  ^[23] This contrasts with permanent scheduling actions, which are subject to formal rulemaking procedures done “on the record after opportunity for a hearing,” and final decisions that conclude the scheduling process and are subject to judicial review.^[24] The specific language chosen by Congress indicates its intent that DEA issue orders instead of proceeding by rulemaking when temporarily scheduling substances. Given that Congress specifically requires the Administrator (as delegated by the Attorney General) to follow rulemaking procedures for other kinds of scheduling actions,^[25] it is noteworthy that, in section 811(h)(1), Congress authorized the issuance of temporary scheduling actions by order rather than by rule.

Even assuming that this action is subject to the notice-and-comment requirements of the APA, the Administrator finds that there is good cause to forgo these requirements pursuant to 5 U.S.C. 553(b)(B), as any further delays in the process for issuing temporary scheduling orders would be impracticable and contrary to the public interest given the manifest urgency to avoid an imminent hazard to public safety.

Although DEA believes this temporary scheduling order is not subject to the notice-and-comment requirements of the APA, DEA notes that in accordance with 21 U.S.C. 811(h)(4), the Administrator took into consideration comments submitted by the then-Acting Assistant Secretary in response to the notices that DEA transmitted to the then-Acting Assistant Secretary pursuant to such subsection.

Further, DEA believes that this temporary scheduling action is not a “rule” as defined by 5 U.S.C. 601(2), and, accordingly, is not subject to the requirements of the Regulatory Flexibility Act (RFA). The requirements for the preparation of an initial regulatory flexibility analysis in 5 U.S.C. 603(a) are not applicable where, as here, DEA is not required by the APA or any other law to publish a general notice of proposed rulemaking. Therefore, in this instance, since DEA believes this temporary scheduling action is not a “rule,” it is not subject to the requirements of the RFA when issuing this temporary action.

In accordance with the principles of Executive Orders (E.O.) 12866 and 13563, this action is not a significant regulatory action. E.O. 12866 directs agencies to assess all costs and benefits of available regulatory alternatives and, if regulation is necessary, to select regulatory approaches that maximize net benefits (including potential economic, environmental, public health, and safety effects; distributive impacts; and equity). E.O. 13563 is supplemental to and reaffirms the principles, structures, and definitions governing regulatory review as established in E.O. 12866. E.O. 12866, Section 3(f), provides the definition of a “significant regulatory action,” requiring review by the Office of Management and Budget. Because this is not a rulemaking action, this is not a significant regulatory action as defined in Section 3(f) of E.O. 12866. In addition, DEA scheduling actions are not subject to either E.O. 14192, Unleashing Prosperity Through Deregulation, or E.O. 14294, Fighting Overcriminalization in Federal Regulations.

This action will not have substantial direct effects on the states, on the relationship between the national government and the states, or on the distribution of power and responsibilities among the various levels of government. Therefore, in accordance with E.O. 13132, it is determined that this action does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons set out above, DEA amends 21 CFR part 1308 as follows:

91 FR 30204