Metamina is the dextroamphetamine molecule with an amino acid attached.  It has to be taken orally and is metabolized to dextroamphetamine.  If it is taken by other direct routes, such as IV or "snorted", it has no effect since the active ingredient is still bound to the amino acid.  It kind of makes it less prone to abuse.  In the US, it is sold under the trade name Vyvanse.  Basically, once metabolized, it's the same as dextroamphetamine or Dexedrene.   BTW, the answer from "forget-me-not" is idiotic.  Desoxyn, chemically methamphetamine hydrochloride, is a valid choice for the treatment of ADHD when other stims don't seem to work.  However, Metamina is not the same as methamphetamine.