Amphetamine

Amphetamine, any of a group of powerful stimulant drugs that act on the central nervous system (the brain and the spinal cord), increasing heart rate and blood pressure while reducing fatigue. Although amphetamines were originally prescribed to suppress appetite and to treat depression, their medical use is now restricted primarily to treating narcolepsy (sudden and uncontrollable sleep attacks) and attention-deficit hyperactivity disorder (ADHD). The amphetamines include drugs that are classified as amphetamines, dextroamphetamines, and methamphetamines.

In the United States, amphetamines used to treat ADHD are marketed under the brand names Adderall and Adderall XR. Adderall is a combination of amphetamine and dextroamphetamine. It is manufactured by Shire Pharmaceuticals.

In February 2006 a special advisory panel to the Food and Drug Administration recommended in an 8-to-7 vote that “black box” warnings be placed on the labels of Adderall and Adderall XR to alert physicians and patients to possible serious effects on the heart and increased risk of heart attack, stroke, or sudden death. Fewer than 10 percent of prescription drugs carry black-box warnings. The warnings mean that the drug could pose significant risks, but doubts about the drug’s safety are not serious enough to withdraw it from the market. Although the panel divided over whether to issue black-box warnings, it agreed unanimously that brochures should be distributed with the drugs to inform patients and their families about the benefits and risks of taking the drugs. The FDA delayed taking any action on the recommendation until it heard from a second advisory panel made up of pediatricians and psychiatrists who are most likely to prescribe the medications. Recommendations are not binding, but the FDA usually follows the advice of its advisory panels.

Amphetamines act by stimulating the release of neurotransmitters such as norepinephrine that increase brain activity and raise blood pressure. When initially taken, amphetamines produce feelings of well-being, increased competence, and alertness. High doses of amphetamines can cause tremors, sweating, heart palpitations, or anxiety. Exhaustion and depression follow when the effects of amphetamines wear off. Serious mental illness including paranoia, delusions, hallucinations, and violent behavior may occur after prolonged use. Since chronic use reduces appetite, weight loss may be drastic, resulting in a gaunt, wasted appearance. Amphetamines are commonly abused by individuals seeking mood elevation, increased alertness, or improved athletic performance.

Methamphetamine abuse has become a serious problem in the United States and other parts of the world. The drug is particularly potent when smoked or injected, and users can quickly become dependent or addicted. The drug’s “high” can be followed by a feeling of depression that makes the user crave more. The drug can also be manufactured with readily available chemicals and over-the-counter drugs, leading to the problem of small-scale “meth labs” set up in homes or even hotel rooms.

Regular medical and recreational use of amphetamines can lead to greater physical tolerance of the drug, requiring progressively higher doses to achieve the same effects. Ultimately, psychological drug dependency may result, characterized by a craving for the drug and belief that one cannot function without taking it (see Drug Dependence).