Tennessee Code Title 39. Criminal Offenses § 39-17-401

(a) This part and title 53, chapter 11, parts 3 and 4 shall be known and may be cited as the “Tennessee Drug Control Act of 1989.”

(b) Except as otherwise expressly permitted by state law, the state preempts the entire field of determining the appropriate sanction for conduct involving a drug or other substance that is classified by this part or title 53, chapter 11, as a Class A or B misdemeanor or a Class A, B, C, D, or E felony. No county, city, town, municipality, or metropolitan form of government has the authority by ordinance, resolution, regulation, or other local law to enact or adopt a sanction for conduct involving a drug or other substance if the sanction for that conduct is established by this part or title 53, chapter 11, as a criminal offense other than a Class C misdemeanor. Any ordinance, resolution, regulation, or other local law enacted or adopted prior to April 12, 2017, regulating drugs and other substances that is inconsistent with this part and title 53, chapter 11, is superseded and repealed. Any policy, guideline, or practice of any agency, department, or employee of a county, city, town, municipality, or metropolitan form of government that regulates or permits the enforcement of conduct covered by this subsection (b) in a manner inconsistent with state law is void.