Methamphetamine, also known as metamfetamine, meth, ice, crystal, glass, tik, N-methylamphetamine, methylamphetamine, and desoxyephedrine, is a psychostimulant of the phenethylamine and amphetamine class of psychoactive drugs. Methamphetamine occurs in two enantiomers, dextrorotary and levorotary; dextromethamphetamine possesses the well-known psychostimulant effects of the drug, while levomethamphetamine is CNS-inactive.