S.C. Code Regs. 38-392.4. Drugs and other substances

(a) No driver shall be on duty and possess, be under the influence of, or use, any of the following drugs or other substances: (1) Any Schedule I drug or other substance identified in appendix D to this regulation; (2) An amphetamine or any formulation thereof (including, but not limited, to "pep pills," and "bennies"); (3) A narcotic drug or any derivative thereof; or (4) Any other substance, to a degree which renders the driver incapable of safely operating a motor vehicle. (b) No motor carrier shall require or permit a driver to violate paragraph (a). (c) Paragraphs (a) (2), (3), and (4) do not apply to the possession or use of a substance administered to a driver by or under the instructions of a licensed medical practitioner, as defined in Regulation 38-382.107 of this regulation, who has advised the driver that the substance will not affect the driver's ability to safely operate a motor vehicle. (d) As used in 38-392, "possession" does not include possession of a substance which is manifested and transported as part of a shipment.