Amphetamines

Currently, amphetamines (AMP) and methamphetamines (MA) are among the most widely abused illicit drugs in the world, second only to marijuana. More than 35 million individuals worldwide use and abuse AMP or MA on a regular basis (as compared with cocaine, which is used by about 15 million people, and heroin, used by fewer than 10 million). As a specific compound in the larger amphetamine family of powerful psychoactive stimulants, MA has become the most popular drug because of its high potency, relative low cost, and ease of manufacture.

Amphetamines were introduced into medical use in the United States in the early 1930s as a nasal spray for the treatment of asthma. By the mid-1960s, the U.S. Food and Drug Administration (FDA) placed the entire class of drugs under regulatory control because of growing concern over its misuse and overuse. Terms to describe the effects of AMP use and users such as “speed freaks” and “speed kills” are an enduring legacy to the phenomena. In the 1970s, regulatory controls on lawfully made AMP were progressively tightened. The Controlled Substances Act, which sorts all regulated substances into one of five schedules based on the substance’s medicinal value, harmfulness, and potential for abuse or addiction, includes AMP and MA in Schedule II (Control Level). These drugs are considered to have a high abuse potential with severe psychic or physical dependence liability.

Methamphetamine is known by a large variety of slang names, including “crystal,” “meth,” or “speed.” It  can  be  injected,  smoked,  snorted,  or  taken  by mouth. The intensity and duration of the “rush” experienced after use is a result of the release of high levels of dopamine into the brain and depends in part on the method of administration. This rush is almost instantaneous when MA is smoked or injected, but takes about 5 minutes after snorting or 20 minutes after oral ingestion. The half-life of MA is 12 hours, giving a duration of effect ranging from 8 to 24 hours (in contrast to the 1-hour half-life of cocaine, giving a high of only 20 to 30 minutes). The use and misuse of MA result from its subjective effects, including euphoria, reduced fatigue, reduced hunger, increased energy, increased sex drive, and increased self-confidence. Although AMP  and  MA  initially  produce  positive effects, the user is typically unaware of negative consequences to many of the body’s systems. Short-term and long-term cardiovascular, respiratory, neurological, cognitive, dermatological, dental, and psychiatric damage may occur in many individuals.

The immediate physiological effects of MA use are like those produced by the fight-or-flight response. As the body prepares for the simulated emergency of the fight-or-flight response, increased blood pressure and heart rate, constricted blood vessels, dilated bronchioles (breathing tubes), and increased blood sugar levels can cause irreversible damage to blood vessels in the brain, producing stroke, respiratory problems, irregular heartbeat, extreme anorexia, cardiovascular collapse, and death. Other negative physical and medical side effects include stomach cramps, shaking, high body temperature, stroke, and cardiac arrhythmia.

Abnormal movements and facial gestures are hallmarks of chronic stimulant abuse, and both acute and chronic use of AMPH and MA may result in coordination problems, shaking, involuntary facial and mouth movements, stereotyped movements, and tics. Abnormal, involuntary movements associated with stimulant use may decrease or end when drug use stops; however, chronic AMP and MA addicts may demonstrate long-lasting movement disorders that may persist for several years after drug withdrawal. Other negative consequences of use include cognitive deficits in memory, attention, concentration, and problem solving. Although some of these deficits may improve over time, enduring deficits may occur in some individuals.

Short-term and long-term AMP or MA use may result in psychological effects such as increased anxiety, insomnia, aggressive tendencies, paranoia, and hallucinations. Of great concern is a psychotic state that may be indistinguishable from paranoid schizophrenia. Paranoid delusions and transient auditory and visual hallucinations are frequent with MA use and its associated psychoses, with as many as two thirds of chronic MA users experiencing delusional psychoses. The delusions may be brief, although it is common for episodes to last several days to months. Of much concern is the violence that often accompanies AMP and MA use, especially in instances of use by parents of young children.

Importantly, the route of administration affects the potential for adverse reactions and associated medical disorders. Intravenous use may result in illnesses associated with the use or sharing of contaminated drug paraphernalia, including human immunodeficiency virus (HIV), hepatitis, tuberculosis, lung infections, pneumonia, bacterial or viral endocarditis, cellulites, wound abscesses, sepsis, thrombosis, renal infarction, and thrombophlebitis. Nasal insufflation (snorting) is associated with sinusitis, loss of sense of smell, congestion, atrophy of nasal mucosa, nosebleeds, perforation or necrosis of the nasal septus, hoarseness, problems with swallowing, throat ailments, and a persistent cough.

Continued use of MA may result in tolerance, and increased use at higher dosage levels may lead to dependence. Investigations of the long-term consequences of MA use in animals indicate that as much as 50% of the dopamine-producing cells in the brain can be damaged even after low levels of MA use, and serotonin-containing  nerve  cells  may  be  damaged even more extensively. Withdrawal effects from discontinuing use of MA often include depression, irritability, fatigue, anergia, anhedonia, and some types of cognitive impairment that last from 2 days to several months.

References:

1. Center for  Substance  Abuse  Treatment  (CSAT).  (1997). Proceedings of the National Consensus Meeting on the use, abuse, and sequelae of abuse of methamphetamine with implications for prevention, treatment, and researc
2. DHHS Pub. No. (SMA) 96–8013. Rockville, MD: Department of Health and Human
3. National Institutes of Health (NIH). (1998). Research report series: Methamphetamine  abuse  and    DHHS Pub. No. 98–4210. Rockville, MD: Department of Health and Human Services.
4. World Health Or (1997). Programme on substance abuse, amphetamine-type stimulants. Geneva: Division of Mental Health and Prevention of Substance Abuse.