(b) Proof of age requirements.--A person making a retail sale of a finished drug product containing any quantity of dextromethorphan shall obtain proof of age from the purchaser before completing the sale unless the purchaser's outward appearance is such that a person would reasonably presume the purchaser to be at least 25 years of age.

(c) Penalty.--A person who is convicted of violating subsection (a) shall be sentenced to pay a fine of not less than $250 nor more than $500 for the first violation and a fine of $500 for each subsequent violation.

(d) Exception.--This section does not apply to a medication containing dextromethorphan that is sold pursuant to a valid prescription.

(e) Preemption.--This section shall be construed to preempt any ordinance regulating the sale, distribution, receipt or possession of dextromethorphan enacted by any political subdivision, and dextromethorphan is not subject to further regulation by political subdivisions.

(f) Definitions.--As used in this section, the following words and phrases shall have the meanings given to them in this subsection unless the context clearly indicates otherwise:

“Finished drug product.” A drug legally marketed under the Federal Food, Drug, and Cosmetic Act (52 Stat. 1040, 21 U.S.C. § 301 et seq.) that is in finished dosage form.

“Proof of age.” A document issued by a governmental agency that contains a description or photograph of a person and gives the person's date of birth, including a passport, military identification card or driver's license.