Any person who knowingly distributes an imitation controlled substance, as defined in section 593 of this chapter, to a person under 18 years of age or to a person who has been adjudged mentally incompetent is guilty of a misdemeanor and shall, if convicted, be subject to imprisonment for not more than one year in jail or a fine of not more than two thousand dollars ($2,000), or both. Upon a second or subsequent conviction of this offense, the person shall be subject to imprisonment for not more than one year in jail and a fine of not less than five thousand dollars ($5,000).