Amphetamine is a potent stimulator of the central nervous system - the brain and nerves of the spinal cord; it plays a medicinal role in a number of diseases. Amphetamine is also highly addictive and has a history of abuse.
In this article, we will look at amphetamine's medical usage, its side effects, and contraindications.
Contents of this article:
Here are some key points about amphetamines. More detail and supporting information is in the main article.
- Amphetamines are central nervous system stimulants
- Amphetamine was first synthesized in Germany in 1887
- The side effects of amphetamine include restlessness, acne, and blurred vision
- There is some evidence that amphetamines might stunt growth in children
- Rarer side effects include seizures, heart problems, and psychosis
History of amphetamine
Over the years, amphetamine has been used to treat numerous ailments.
Amphetamine was first synthesized in 1887 by Lazăr Edeleanu, a Romanian chemist working in Germany, who named it phenylisopropylamine.
The chemical's stimulant properties were not known until 1927, and amphetamine was not used medically until 1934 when it was marketed as a decongestant.
Under the trade name Benzedrine, amphetamine was used (with mixed results) to treat conditions such as epilepsy, Parkinson's disease, fatigue, depression, schizophrenia, alcoholism and other addictions, myasthenia gravis (a condition of muscle weakness), migraine, sea sickness, and persistent hiccups.
During World War II, amphetamine and methamphetamine (a similar chemical) were used for their performance-enhancing and stimulant effects. For instance, bomber pilots would use amphetamines to remain alert on long missions. However, amphetamine was predominantly used by the allied forces because it increased confidence and aggression and elevated morale.
In the 1950s, so-called pep pills that included amphetamine were used by truck drivers, students, homemakers, and athletes to provide extra energy and promote wakefulness. As amphetamine's addictive properties became known, countries began to control and ban the drug.
What does amphetamine do?
By activating specific receptors, amphetamine increases the activity of a number of neurotransmitters, especially norepinephrine and dopamine. These alterations cause changes in libido, increase wakefulness, improve cognitive control, and produce euphoria.
Physically, amphetamine can decrease reaction times, increase muscle strength, and reduce fatigue.
At higher doses, amphetamine reduces cognitive ability and breaks down muscle. At very high doses, psychosis, including delusions and paranoia, can occur. Addiction is also a serious risk at high doses.
A class of drugs based on the structure of amphetamine, referred to as substituted amphetamines, include methamphetamine, cathinone, ephedrine, MDMA (ecstasy), and 2,5-Dimethoxy-4-methylamphetamine (DOM). Substituted amphetamines have a wide variety of overlapping effects that broadly fit into three categories:
- Psychoanaleptic: drugs with an arousing effect
- Hallucinogen: causing hallucinations (visual, auditory, or other), perceptual anomalies
- Empathogen: increased feelings of "oneness," empathy, and emotional openness.
Medical uses of amphetamine
Although amphetamine has been trialed for a wide variety of conditions, its primary uses in modern medicine are for treating the following conditions:
Attention deficit hyperactivity disorder
ADHD is characterized by hyperactivity, irritability, mood instability, attention difficulties, lack of organization, and impulsive behaviors. The disorder is estimated to affect 11 percent of children.
Amphetamines reverse some of these symptoms and have been shown to improve brain development and nerve growth in children with ADHD. Long-term treatment of amphetamine-based medication in children appears to decrease abnormal brain function and structure.
ADHD sometimes persists into adulthood, but amphetamines are less useful in older individuals; the side effects often prompt adults to cease taking the medication.
Narcolepsy is characterized by excessive daytime sleepiness and irresistible sleep episodes, called "sleep attacks." Strong emotions can trigger a sudden and unstoppable loss of muscle tone (cataplexy) and bouts of sleep.
Amphetamines have been used to treat narcolepsy since the 1930s. An amphetamine derivative - methylphenidate - which has fewer side effects, has also been used. Because of the side effects of amphetamines, they are increasingly being replaced by modafinil, a medication that promotes wakefulness.
Amphetamines, marketed as Benzedrine, were first used as a way to treat obesity in the 1930s. They increased in popularity over the following decades due to their appetite-suppressing capabilities.
Although amphetamine use to treat obesity has fallen, a recent small-scale trial using dexamphetamine, a similar molecule to amphetamine, has shown some promise. The appetite reduction, improved cognitive control, and reduction in compulsive behavior attributed to the drug produced significant weight loss in a 6-month trial involving just 12 individuals.
However, because of the side effects and the potential for addiction and abuse, medical professionals generally do not recommend amphetamines and their derivatives to help reduce obesity.
Amphetamines are (rarely) used to treat types of depression that do not respond to other treatments, particularly in individuals whose depression predominantly features fatigue and apathy.
In these cases, amphetamines (and other psychostimulants) may be used in conjunction with standard antidepressant medication.
In a study that followed 65 patients taking amphetamines alongside normal medication, 38 "showed significant improvement, in particular with respect to energy, mood, and psychomotor activity." According to the authors, side effects were minimal, and no drug dependency was seen.
Side effects of amphetamine
Amphetamine has the potential to produce many side effects; they vary in severity.
Physical side effects of amphetamine
- Hypertension or hypotension (low or high blood pressure)
- Raynaud's phenomenon (reduced blood flow to extremities)
- Erectile dysfunction (frequent or persistent erections)
- Tachycardia (increased heart rate)
- Abdominal pain, loss of appetite, nausea, weight loss
- Acne, rash, hives
- Blurred vision
- Dry mouth
- Teeth grinding
- Profuse sweating
- Nasal congestion
- Increased likelihood of seizures for susceptible individuals
- Faster, deeper breaths (especially for individuals with other lung conditions)
- Difficulty urinating (due to constriction of the urinary bladder sphincter)
Psychological side effects of amphetamine
One potential psychological side effect of amphetamine is mood swings.
- Increased alertness
- Mood swings
- Changes in libido
- Obsessive behaviors
- Psychosis (rare)
Addiction is a serious risk if amphetamines are taken recreationally, but at typical therapeutic doses, the chances of becoming addicted are very low.
There is evidence that amphetamine use to treat ADHD could stunt growth in children. However, some studies show that any reduction in growth speed may be caught up by a "growth rebound" once the drug has stopped being taken.
Some preexisting conditions can make certain drugs unsafe to take - these are known as "contraindications."
Contraindications for amphetamines include:
- Sensitivity to amphetamines or their derivatives
- Advanced arteriosclerosis (thickening or hardening of artery walls)
- Propensity for agitation
- Glaucoma (pressure within the eye)
- Previous drug abuse
- Hyperthyroidism (overactive thyroid)
- Moderate to severe hypertension (high blood pressure)
- Cardiovascular disease
- Use of MAO (monoamine oxidase) inhibitors within the past 2 weeks (these include moclobemide and toloxatone)