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The nonmedical use or abuse of, or dependence on, psychostimulants including:
Amphetamines were first used as a nasal decongestant and then by the U.S. military to improve alertness in troops. In the 1950s, they gained popularity as weight-loss drugs (i.e., ephedra, ma huang) and became drugs of abuse. They enhance neurotransmitter (esp. dopamine, norepinephrine) activity in the mesocorticolimbic pathway due to effects on monoamine transporters.
Cocaine is a tropane ester alkaloid found in leaves of the Erythroxylum coca plant that enhances monoamine neurotransmitter (dopamine, norepinephrine, and serotonin) activity by blocking presynaptic reuptake. It also enhances activity in the corticomesolimbic dopamine reward circuit. Smoking or IV use has effects lasting 15-30 min; effects from snorting and gastrointestinal absorption last 1-3 hours.
Cocaine base ("crack," "freebase") can be smoked because it has a relatively low melting point (98ºC) and vaporizes. It is rarely injected because it is relatively insoluble. Onset of action within seconds.
Cocaine HCl cannot be efficiently smoked because it melts at 195ºC with substantial loss of the active metabolites. Cocaine salt is readily injected or insufflated ("snorted") through the nose; it is highly water soluble with onset of action within 20-30 minutes.
Methamphetamine is a psychostimulant that is a derivative of amphetamines and increases the release and blocks the reuptake of monoamine neurotransmitters. Starting in the late 1980s, use of methamphetamine has evolved to include a wider range of the population and of the country (used to be localized mostly to CA and OR). Street names include crystal meth, crank, ice, chalk, and Tina.
Synthetic cathinones (AKA "bath salts") are beta-ketone amphetamine analogs that encompasses a large array of chemicals that do not always have the same pharmacologic properties. They are reported to increase energy, empathy, and libido (associated with high-risk sexual behavior). They emerged as a substance of abuse in Europe in 2009 and spread to the U.S. in 2010.