The Course of Caffeine

Updated on January 19, 2018
Ktina Amber profile image

As a psychology major, I attended a class called psychopharmacology. I grew intrigued with the way substances affected both body and brain.

Just right!
Just right! | Source

General Description

Caffeine is a psychoactive drug that belongs to the xanthine’s family. Caffeine is known as a stimulant. Ferre (2015) states caffeine produces psycho motor-activating, reinforcing, and arousing effects. According to Advokat (2014) caffeine stimulates the central nervous system, produces urine, stimulates cardiac muscles, as well as soothes and relaxes muscles. Caffeine is organically found in coffee beans, tea leaves, the kola nut and the cocoa bean (Advokat, 2014). While caffeine is found in these plants; people have been known to harvest it and use it for recreational purposes; caffeine is most commonly found in drinks like coffee, tea and soda; however there are also instances where caffeine is an additive in headache medications. It is believed that people drink several cups of coffee to help fight the risks of cancer; they take green coffee bean as a substance to aid with weight loss, not to mention caffeine can be beneficial when pertaining to protection against liver disease and can decrease gout as well as it produces a protective effect again Parkinson’s disease (Advokat, 2014). There has also been evidence stating caffeine may also decrease the risk of Alzheimer’s disease. Though caffeine does have these possible health benefits, the general consumption is related to its ability to increase physical endurance, improve concentration, elevate moods, and enhance motor performance, as well as reducing fatigue and delaying the need for sleep (Advokat, 2014). Kadley (2016) adds that caffeine may also be able to improve alertness, short-term memory, and well protects against depression.

Route of Administration, Half-Life, Doses

Since typically found in drinks and medicine caffeine is orally ingested. Caffeine is known to be water and oil soluble; thus it is rapidly absorbed and equally distributed throughout the body and the brain (Advokat, 2014). Advokat (2014) state the average cup of coffee has about 135 milligrams of caffeine; while average drinkers drink 2-5 cups equating to 200- 500 milligrams per day. The half-life of elimination can range from 2.5 to 10 hours; however the rate can vary based on the individual. If the individual is a smoker the metabolism rate is faster, as opposed to those who drink caffeine with alcohol, the half-life is extended (Advokat, 2014).


Adenosine receptors are commonly blocked by caffeine; therefore it is known as adenosine antagonist. Advokat (2014) states adenosine is known as a neuromodulator and it release several different neurotransmitters within the central nervous system. As the day goes on adenosine increases and causes a sleep-induced effect on the brain (Advokat, 2014). Therefore since caffeine is known to be an adenosine antagonist it causes the opposite effect of wakefulness. Behavior is also affects by its adenosine antagonist properties; as it removes negative modulatory effects of adenosine from dopamine receptors. Ferre (2015) states caffeine serves as a blockade of adenosine neuro-transmission; and psycho-stimulants elicit their psycho motor-activating and reinforcing effects by their ability to increase central dopamine neuro-transmission.

But, caffeine doens't make you sleepy!
But, caffeine doens't make you sleepy! | Source

Drug Interactions and Side Effects

There is a subgroup of a drug-metabolizing enzyme known as CYP-1A2 that is responsible for metabolizing caffeine. Antidepressants such as fluoxetine and fluvoxamine are known to be potent inhibitors of CYP-1A2; therefore those who take those antidepressants can experience a high intolerance to caffeine where severe anxiety reactions can form (Advokat, 2014). When caffeine is combining with alcohol, individuals typically think they will negate each other’s effects however that are not known to be true. Caffeine can aid in reducing some of the effects of alcohol; however it in fact enhances alcohol tolerance and can contribute to alcohol dependence since it counteracts symptoms of a hangover (Advokat, 2014). Individuals who suffer from anxiety disorders may be more sensitive to the anxiogenic properties of caffeine. While others who drink coffee on a regular basis, may experience increased occurrences of headaches, and disturbances in their sleep cycles. Though there may be instances where one can fall asleep; the duration, quality and repeated awakenings may be affected (Advokat, 2014). Kadley, 2016 states there are many health concerns that are related to over usage of caffeine; such concerns are cardiovascular concerns, insomnia, poor food choices, risky behavior, sugar blues, and dental problems. Too much caffeine can over stimulate the central nervous system; which can lead to increase or irregular heart rate and even cause a rise in blood pressure thus there is the possibly of caffeinated drinks causing cardiac arrest (Kadley, 2016). Since the half-life if caffeine can stay in your system for up to 10 hours, even if ingested in early hours of the day, it can alter your circadian clock; therefore making it difficult to fall asleep at regular hours. Poor food choices can be made by those who over consume coffee, and energy drinks, as they are full from those drinks therefore leading to skipping meals. Also pertaining to drug interactions, mixing caffeine and alcohol can result in risky behavior, since the simulating effects of caffeine are counteracting the sedation effects of alcohol. Kadley (2016) describes sugar blues as blood sugar levels constantly elevated by continuous ingestion of sugary caffeinated drinks; thus possibly leading to obesity, diabetes, and heart disease. Finally Kadley mentions there is the possibility for dental issues. Coffee is known to stain teeth, as energy drinks are likely to have high acidity levels that can erode tooth enamel.

Can't live without it!
Can't live without it! | Source

Caffeine Abuse

Though caffeine is not an illegal drug there are still instances when individuals over use the drug. When caffeine is ingested regularly too much or too little can affect and individual’s mental acuity (Ruscigno, 2016). With constant consumption of the drug a tolerance is acquired. As the tolerance is acquired in order to get the same effect there may need to be an increase in the consumption of the drug. With the buildup of tolerance there may also become an established dependence of caffeine. If dependence is formed and there is a discontinuation of the drug withdrawal symptoms may become present. Those symptoms include headache, drowsiness, fatigue, and difficulty concentrating (Advokat, 2014). Commonly if caffeine is re-administered the effects of withdrawal will be subsided. However slowly reducing caffeine can reduce caffeine-withdrawal symptoms (Ruscigno, 2016). There are some who choose not to fight their habitual caffeine intake and over use the drug. The overuse of caffeine is known as caffeinism; this can cause anxiety, agitation, insomnia, as well as mood changes not to mention hypertension, cardiac arrhythmia, and gastrointestinal disturbances (Advokat, 2014). Psychosis is possible when there are prolonged experiences of caffeinism. Caffeinism typically occurs when individuals ingest 500-1000 milligrams or the equivalent to 5-10 cups of coffee.


Advokat, C. D., Comaty, J. E., & Julien, R. M. (2014). Julien's primer of drug action: A comprehensive guide to the actions, uses, and side effects of psychoactive drugs (13th Ed.). New York, NY: Worth Publishers.

Ferre, S. (2015). Mechanisms of the psychostimulant effects of caffeine: implications for substance use disorders. Psychopharmacology. 233. 1963-1979. Kadley, M. (2016). Caffeine Overdrive. Environmental Nutrition. 39(1). 4

Ruscigno, M. (2016). Brain Fog and Diet. Environmental Nutrition. 39(10). 3

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    © 2018 Kristina


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