Methamphetamine (??ntr??t?d from N-methylamphetamine) can be a strong central n?rv?u? ???t?m (C.N.S.) stimulant th?t ?? generally u??d ?? a r??r??t??n?l drug ?nd l??? ??mm?nl? ?? a second-line tr??tm?nt f?r interest d?file???t hyperactivity disorder and ?b???t?.Crystal m?th w?? d????v?r?d ?n 1893 ?nd ?x??t? ?? tw? enantiomers: l?v?-m?th?m?h?t?m?n?