; (B) marketed or packaged to appear similar to a candy or beverage product; or (C) modified by flavoring or coloring to appear similar to a candy or beverage product; and (2) knowing, or having reasonable cause to believe, that the controlled substance will be distributed, dispensed, or sold to a person under 18 years of age. (b) The penalty described in this subsection is— (1) in the case of a first offense involving the same controlled substance and schedule, an additional term of imprisonment of not more than 10 years; and (2) in the case of a second or subsequent offense involving the same controlled substance and schedule, an additional term of imprisonment of not more than 20 years. (c) Subsection (a) shall not apply to any controlled substance that— (1) has been approved by the Secretary under section 505 of the Federal Food, Drug, and Cosmetic Act ( 21 U.S.C. 355 ), if the contents, marketing, and packaging of the controlled substance have not been altered from the form approved by the Secretary; or (2) has been altered at the direction of a practitioner who is acting for a legitimate medical purpose in the usual course of professional practice. . (b) Technical and conforming amendment The table of contents for the Comprehensive Drug Abuse Prevention and Control Act of 1970 ( Public Law 91–513