Common Stimulants Drugs
Written by John Tran
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Stimulants, also known as “uppers”, have the central (i.e. the brain) effect of elevating mood, increasing awareness of surroundings, focus, attention and possibly euphoria. Physiologically, these drugs tend to affect the cardiovascular and respiratory systems. These include increased blood pressure and higher heart rate. In the lungs, the airways are relaxed to allow greater oxygen consumption due to the heart’s increased workload. If the stimulants drug is continually used at a higher concentration, these seemingly favorable effects lead to deleterious results.
The sustained hyperactivity may result in decreased attention and focus, leading to harm to the user or people nearby. The hyperactivity is often exhibited by the user as rage. Internally, the overstimulation of neurons may result in damage or even cell death, while hyperactivity in the heart may cause it to give way to cardiac arrest and possibly death. However, chronic users do develop tolerance over time, and their physiology becomes altered to handle drug abuse. The euphoric effects of stimulants are generally what make them addictive, but withdrawal symptoms such as lethargy, depressed or irritable mood, anxiety, fatigue, and lack of pleasure can reinforce abuse of stimulants. In most cases, sleep follows after the effects of the stimulant wear off because the user is tired. Some common stimulants include caffeine, cocaine and amphetamines. Their descriptions are given below.
Caffeine
Caffeine is often found in drinks such as soda, tea and coffee, and it is primarily used to ward off drowsiness so the user can concentrate on tasks that require focus and attention. These energy drinks have become popular in younger generations such as Red Bull and Rockstar. Interestingly, caffeine is also used as a pain reliever and a dietary supplement. In small amounts, such as those found in Excedrin, caffeine seems to aid in headache pain relief. “Muscle builders” utilize caffeine as a means to delay fatigue and increase endurance thereby build more muscle, though there is controversy in this area as whether this is true or not. Caffeine is a diuretic (i.e. induces urination) that can result in dehydration which may hurt exercise. Most of the effects induced by caffeine are the result of inhibiting adenosine receptors. Though the mechanism of action with respect to alertness is not clearly understood, research suggests that adenosine receptor activation leads to functions that protect the brain, such as suppression of neural activity and increased cerebral blood flow that induces drowsiness, eventually leading to sleep. Hence by blocking central adenosine receptors, caffeine allows the opposite to happen, which is wakefulness.
Normal caffeine usage (e.g. two cups of coffee a day) does not seem to adversely affect human health, but when used in higher concentrations, some mild effects can ensue. They include nervousness, “fidgety” behavior (anxiety), shivers, insomnia, and loss of focus. Overuse can also lead to dehydration and muscle cramping. These effects decrease with stoppage, but chronic users develop tolerance that allows them to handle increased caffeine concentrations. This tolerance also indicates that more caffeine is needed to get the same benefits of wakefulness and alertness. After chronic use of caffeine, ending use leads to mild withdrawal symptoms which are commonly exhibited as irritability, anxiety, fatigue and headaches. These symptoms may last up to seven days. Chronic use of caffeine does not seem to lead to discernable problems by itself, but may worsen underlying condition such as heart disease. Theoretically the increased heart rate and high blood pressure as a result of drinking caffeinated drinks over time, amplifies changes in the heart caused by high cholesterol, obesity and diabetes.
Cocaine
Cocaine is a serious stimulant with profound effects. It can be found in a white, powdery form but is usually converted into a “free base” form that is popular among recreational users for smoking. If cocaine is not smoked, the white powder is snorted, taken orally (in small amounts) or injected intravenously. After it enters the body, cocaine reaches the brain where it changes neurotransmitter levels. Current research indicates the mechanism of action is inhibition of neuronal reuptake of norepinephrine (or noradrenaline) and dopamine. Reuptake is a mechanism where neurotransmitters are taken back by the neurons that released them. This stops neural activation and transmission. Blockage of neuronal reuptake means that these neurotransmitters exist in larger than usual amounts in the synaptic area, inducing greater neuronal transmission and activation. This prolonged activation leads to symptoms that include euphoria, mental alertness, talkative behavior, insomnia, and decreased food intake. Some claim physical and mental tasks are done with clarity and completed quicker under the influence of cocaine. It is no wonder that it is a banned substance in different athletic sports.
Physically, cocaine use is visible as rapid heartbeat, sweating, and high temperature. This is probably the result of blockage of norepinephrine and epinephrine in the periphery (outside the brain) in addition to central effects. An interesting fact that many may not know is cocaine can be used as a local anesthetic. The mechanism of action for anesthesia is it blocks peripheral nerve endings where touch is sensed.
The dependency of cocaine is due to its inhibition of dopamine reuptake in neurons, especially in the brain region, the nucleus accumbens the suggested central area for pleasure and reward. Having increased brain activity in this area reinforces cocaine craving-and-seeking behavior. Making this dependency even worse is the tolerance that develops in chronic users. More and more cocaine is needed to reach the same “high” that the user once had at a previously lower level. Cocaine withdrawal symptoms are like others in the stimulant class, where lethargy, tremors and shakes, headaches, agitation, lack of pleasure and drowsiness are present. Amazingly, cocaine withdrawal symptoms, unlike other drugs, present themselves right after the euphoric effects of cocaine wear off. This can be seen as a “crash,” which often is sleep. The user seeks more cocaine to block this withdrawal, as much as possible until the money runs out.
Treatment for cocaine dependency involves mainly psychological and some pharmacological intervention. Most of the psychological treatment revolves around changing drug seeking behavior. These include cognitive and behavioral therapies. It is not unusual to use interpersonal strategies as well. This is because cocaine abusers generally become isolated from others and regress in the ability to interact with society. Depression is also prevalent among chronic users and some clinicians prescribe antidepressants as adjuvant therapy. Presently, there are no FDA-approved pharmacological agents that treat cocaine abuse directly, other than emergency treatment for overdose or cardiac arrest. Underlying issues are often at the core of most abuse. A treatment plan that helps discover and process such issues would be highly beneficial.
Amphetamine
Amphetamine and its derivatives are numerous and can be found throughout as treatments for a variety of clinical indications. Popular indications include attention-deficit hyperactivity disorder (ADHD; methylphenidate – Ritalin), narcolepsy, colds (pseudophedrine), and in some countries, weight loss (ephedrine). Amphetamines can also be used illicitly such as taking speed (methamphetamine) or ecstasy (MDMA). If used for medical purposes, amphetamines are taken orally and generally have no addictive properties, mostly due to their low quantity. However, if they are used outside the realm of medicine or already taken illegally such as intravenously injected methamphetamine, dependency can happen. These drugs can become addictive because they act by increasing dopamine transmission in areas of reward and pleasure. The mechanism of action seems to involve binding the transporter that reuptakes dopamine and reverses it, thereby allowing release of more dopamine into the synapse for more neuroactivation. This is unlike cocaine where inhibition of reuptake does not reverse the transporter.
Interestingly, amphetamine’s actions are not only limited to dopamine. In terms of its pharmacology, it is known as a dirty drug where it produces effects by binding or affecting more than one type of receptor. Some of these notable sites involve receptors for serotonin and norepinephrine. These areas are important in focus, attention and wakefulness. Overactivation of these receptors, especially in illicit use, may lead to euphoria, anxiety, creative thinking, mental sharpness, and excitability. Physically, these effects are similar to other types of stimulants, which include increased heart rate, sweating, blurred vision, headache and insomnia. The types of effects that are seen depend on the type of amphetamine that is used. For example, ecstasy produces hyperexcitability and the user can be awake for a prolonged amount of time without feeling tired due to MDMA’s preference for serotonin receptors, which are important in wakefulness.
Chronic overuse of amphetamines can lead to dependency, but the dependency is more rampant with recreational use (e.g. methamphetamines and MDMA). Withdrawal to amphetamines, unlike cocaine, comes on slower but may last longer, even up three weeks. These symptoms include increased appetite, depression, sleepiness, lethargy, and fatigue. Treatment for amphetamine abuse at the current moment involves psychological intervention as a means to change the behavior of the user. As for drugs, antidepressants are utilized to combat the depression and mood disorders. There is some research that indicates that opiates can help treat dependency, specifically for methamphetamine, but the reasons to why they are effective are unclear. One possible idea is that both heroin and methamphetamine are both intravenously injected and opiates provide relief in that type of route of administration. Treatment is useless however, especially in the case of MDMA, when brain cells are permanently damaged probably due to the result of the neural hyperactivity. In that condition, the belief is that neurons become overstimulated, “short” (like in a short circuit), and die off. Ecstasy use is dangerous and all treatment efforts should be on the prevention side.
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