Methamphetamine is a highly addictive drug with potent central nervous system (CNS) stimulant properties. In the 1960s, methamphetamine pharmaceutical products were widely available and extensively diverted and abused. The 1971 placement of methamphetamine into schedule II of the Controlled Substance Act (CSA) and the removal of methamphetamine injectable formulations from the United States market, combined with a better appreciation for its high abuse potential, led to a drastic reduction in the abuse of this drug. However, a resurgence of methamphetamine abuse occurred in the 1980s and it is currently considered a major drug of abuse. The widespread availability of methamphetamine today is largely fueled by illicit production in large and small clandestine laboratories throughout the United States and illegal production and importation from Mexico. In some areas of the country methamphetamine abuse has outpaced heroin and cocaine.

Methamphetamine was originally used in nasal decongestants and bronchial inhalers (the levo isomere of methamphetamine is still utilized for these indications). Later it was available in tablets and injectable formulations and used for weight control, depression, and to increase alertness and prevent sleep. A broad segment of society from housewives to truckers to military personnel used methamphetamine products for stimulant effects. Today there is only one product, Desoxyn®, currently marketed in 5 mg tablets. Desoxyn® has very limited use in the treatment of obesity, and attention deficit hyperactivity disorder.

Methamphetamine is chemically and pharmacologically similar to amphetamine although it has more potent effects on the CNS that can last for 6 to 8 hours. Methamphetamine increases the release of the neurotransmitter, dopamine, which stimulates brain cells, enhancing mood and energy. At low doses, methamphetamine produces such effects as increased wakefulness, increased physical activity, increased heart rate and blood pressure, decreased appetite, increased respiration and body temperature (hyperthermia), and euphoria. High-dose chronic use has been associated with irritability, tremors, convulsions, anxiety, paranoia, and neurotoxic effects that cause damage to neurons and blood vessels. Aggressive and violent behavior, often directed at spouses and children, pose a significant risk to those individuals in contact with methamphetamine addicts. Death has resulted from extreme anorexia, hyperthermia, convulsions, and cardiovascular collapse (including stroke and heart attacks).

Methamphetamine is abused for its stimulant and euphoric effects. It can be taken orally, snorted, smoked, and injected. Smoking or injecting methamphetamine results in intense euphoria and is often associated with binge use, large escalation in dose with rapid tissue tolerance, and high rates of dependence and addiction. "Ice," "Glass," and "Crystal" are all terms for concentrated d-methamphetamine HCl chunks that are smoked. Yaba is a Thai name for a colored tablet containing methamphetamine combined with caffeine which is gaining popularity among individuals who frequent "raves." According to the 2006 National Survey on Drug Use and Health, 5.8% of individuals ages of 12 and older reported illicit use of methamphetamine at least once in their lifetime and 731,000 (0.3%) reported current use.

Mexican drug trafficking organizations have become the primary manufacturers and distributors of methamphetamine to cities in the Midwest and West. These criminal organizations are able to supply large amounts of methamphetamine at high purity and low cost. Domestic independent laboratory operators also produce and distribute methamphetamine but usually on a smaller scale. These domestic laboratories have proliferated, spreading from the West Coast to the East Coast. In 2005 and 2006, the El Paso Intelligence Center National Clandestine Laboratory database reported seizures of 12,613 and 7,177 methamphetamine laboratories (including active labs, boxed labs, and dumpsites), respectively. In 2005, the five states reporting the greatest number of lab seizures included Missouri (2,195), Indiana (1,014), Illinois (944), Tennessee (870), and Iowa (765). In 2006, Missouri (1,275), Indiana (778), Illinois (769) and Tennessee (661) reported the largest number of lab seizures. Most were small laboratories with some only producing personal-use amounts. Of particular concern is the toxic waste associated with these labs and the fact that many individuals, including children, are at risk of exposure to these toxic chemicals.

There are many ways to manufacture methamphetamine. The methods used are directly impacted by the availability of precursor chemicals and ease of synthesis. Drug traffickers are continuously looking for loopholes in chemical control regulations and altering their methods of synthesis in order to continue their illegal activity. Currently, methamphetamine is primarily produced by utilizing diverted pseudoephedrine combination products. The Combat Methamphetamine Epidemic Act of 2005 requires retailers of non-prescription products containing pseudoephedrine, ephedrine and phenylpropanolamine to place these products behind the counter or in a locked cabinet. Consumers must show identification and sign a logbook for each purchase.

Methamphetamine is in schedule II of the CSA.