(a) Unless otherwise provided in this chapter, a person convicted of a second or subsequent offense under this chapter shall be imprisoned for a term up to two (2) times the term otherwise authorized, fined an amount up to two (2) times the fine otherwise authorized, or both.
(b) For purposes of this section, an offense is considered a second or subsequent offense if, before his or her conviction of the offense, the offender has at any time been convicted under this chapter or under any statute of the United States or of any state relating to a narcotic drug, marijuana, depressant, stimulant, or a hallucinogenic drug.
(c) This section does not apply to an offense under § 5-64-419 or § 5-64-441.