Methamphetamine as a street drug: effects, addiction, and associated risk factors

Methamphetamine is the most prevalent amphetamine-type stimulant, which is often illicitly produced in clandestine or laboratory settings from prescription or over-the-counter drugs. Methamphetamine has more than 20 street names, with “crystal,” “glass,” and “hot ice” being among the most popular. Crystal methamphetamine resembles shards of colorless or light blue glass; however, the drug is often used as powders, tablets, pills, smoking mixtures, and/or solutions for injection. Methamphetamine may be administered by various routes, including oral, rectal, respiratory (via vapor/smoke inhalation), intravenous (via injections), and vaginal. It is generally absorbed through mucous membranes and crosses the blood-brain barrier. The physiological effects of methamphetamine are similar to those of amphetamine-type drugs. These are the result of stimulation of the central nervous system, the sympathetic part of the vegetative nervous system, and the cardiovascular system, with simultaneous suppression of the digestive tract function. Therefore, the effects of this group are similar to the physiological and psychological effects of epinephrine, known as the fight-or-flight response. These changes include stimulation of mental abilities, attention, reactivity, alertness, and anxiety (vigilance); improvement of mood (elimination of depression symptoms) and self-esteem; insomnia; increased muscle activity; and fatigue relief (the doping effect). They also provoke increased heart rate, blood pressure, body temperature, perspiration, respiratory rate, and blood sugar levels accompanied by suppression of appetite; constriction of peripheral arterial vessels; bronchial and pupillary dilation; decreased peristalsis of atonic intestines, stomach, gallbladder, biliary tract, and ureters; reduced secretory function of digestive glands; and dry mouth. High doses may induce paranoia, exacerbation of schizophrenia, seizures, cardiovascular collapse, stroke, or death. The effects of methamphetamine typically persist for 6–12 h, with maximum duration reaching up to 24 h at high doses. The biological half-life of methamphetamine in adults is 4–5 h. The substance is recognized as a highly addictive drug with a high potential for abuse. Consequently, it is classified as a narcotic drug worldwide.