1. Short title This Act may be cited as the Continuous and Enduring Action to Stop Every Overdose Act of 2023 or the CEASE Overdose Act of 2023 . 2. Class scheduling of fentanyl-related substances Section 202(c) of the Controlled Substances Act ( 21 U.S.C. 812(c) ) is amended by adding at the end of schedule I the following: (e) (1) Unless specifically exempted or unless listed in another schedule, any material, compound, mixture, or preparation which contains any quantity of a fentanyl-related substance, or which contains the salts, isomers, and salts of isomers of a fentanyl-related substance whenever the existence of such salts, isomers, and salts of isomers is possible within the specific chemical designation. (2) For purposes of paragraph (1), except as provided in paragraph (3), the term fentanyl-related substance means any substance that is structurally related to fentanyl by 1 or more of the following modifications: (A) By replacement of the phenyl portion of the phenethyl group by any monocycle, whether or not further substituted in or on the monocycle. (B) By substitution in or on the phenethyl group with alkyl, alkenyl, alkoxyl, hydroxyl, halo, haloalkyl, amino, or nitro groups. (C) By substitution in or on the piperidine ring with alkyl, alkenyl, alkoxyl, ester, ether, hydroxyl, halo, haloalkyl, amino, or nitro groups. (D) By replacement of the aniline ring with any aromatic monocycle whether or not further substituted in or on the aromatic monocycle. (E) By replacement of the N-propionyl group with another acyl group. (3) A substance that satisfies the definition of the term fentanyl-related substance in paragraph (2) shall nonetheless not be treated as a fentanyl-related substance subject to this schedule if the substance— (A) is controlled by action of the Attorney General under section 201; or (B) is otherwise expressly listed in a schedule other than this schedule. .