Okla. Stat. tit. 63, § 63-2-412: Second or subsequent offenses

An offense shall be considered a second or subsequent offense

under this act, if, prior to his conviction of the offense, the

offender has at any time been convicted of an offense or offenses

under this act, under any statute of the United States, or of any

state relating to narcotic drugs, marihuana, depressant, stimulant,

or hallucinogenic drugs, as defined by this act.