Methamphetamine (/mɛθæm'fɛtəmiːn/ also known as metamfetamine (INN), methylamphetamine, N-methylamphetamine, and desoxyephedrine) is a psychostimulant and sympathomimetic drug.
A member of the family of phenylethylamines, methamphetamine is chiral, with two isomers:
The levorotary form, called levomethamphetamine, is an over-the-counter drug used in inhalers for nasal decongestion. Levomethamphetamine does not possess any significant central nervous system activity or addictive properties. The remainder of this article deals only with the dextrorotatory form, called dextromethamphetamine, and the racemic form.
Methamphetamine enters the brain and triggers a cascading release of dopamine, serotonin and norepinephrine. It is highly active in the mesolimbic reward pathways of the brain, inducing intense euphoria, with risk for addiction. To a lesser extent, methamphetamine acts as a dopaminergic and adrenergic reuptake inhibitor with high concentrations serving as a monoamine oxidase inhibitor. Users may become hypersexual or obsessed with a task, thought or activity. Withdrawal is characterized by excessive sleeping, eating, and major depression, often accompanied by anxiety and drug-craving. Methamphetamine users may take sedatives such as benzodiazepines as a means of easing their "come down", anxiety or enable them to sleep.
Methamphetamine has medical uses as well as the potential to cause addiction. Methamphetamine addiction typically occurs when a person begins to use the drug as a stimulant, for its powerful enhancing effects on sex, mood and energy, alertness and ability to concentrate, and weight loss and appetite suppression, among its other psychological and physical effects. Over time tolerance develops, and users have greater difficulty functioning and experiencing pleasure than they did before, which persists indefinitely due to neurotoxicity produced by methamphetamine in long-term recovered addicts.
Nicknames for methamphetamine are numerous and vary significantly from region to region, some common nicknames for methamphetamine include "crank", "meth", "ice", "crystal", "glass", "shabu" or "syabu" (Philippines), "tik" (South Africa), "P" (New Zealand), "piko" (Slovakia), and "yaa baa" (Thailand). Methamphetamine is sometimes referred to as "speed", but this term is generally reserved for regular amphetamine and dextroamphetamine.