Introduction to Caffeine

[​IMG]Caffeine is a mild psychostimulant drug both popular and legal the world over; caffeine is commonly utilized in order to increase alertness and fight the symptoms of fatigue, namely drowsiness. It is a xanthine alkaloid produced naturally by several plants, although it can also be synthesized. (Granted, there is little reason to do so, since caffeine is so abundant in plant sources and is easily extracted.) Unlike most stimulants, caffeine is legal to possess, use, distribute, buy, sell, and transport in almost every country.

While the consumption of caffeine is often practical, rather than recreational, it is overall, by far, one of the most commonly used psychoactive drugs. It is estimated that 90 percent of adults in North America alone consume caffeine on a daily basis.

Caffeine is related to other methylxanthine stimulants, all of which bear xanthine (or xanthic acid) as their base molecule. This class of drugs most notably includes theophylline and theobromine. Caffeine also has various synthetic analogs.

Using Caffeine

Caffeine is widely employed for promoting energy and vitality, and diminishing fatigue and sleepiness; it provides a temporary pick-me-up, so to speak. Many different products contain the drug, and it is relatively common for a person to consume caffeine within the course of a day and not even realize it. Products such as tea and certain sodas are falsely believed by many not to contain caffeine. The drug has many uses in modern society, from warding off somnolence to causing euphoria (albeit very mild).

Ways of administration:

Caffeine can be used in a number of different ways, although oral administration is by far the most common. Under most circumstances, caffeine is consumed as either an additive or natural product found within various types of beverages. Examples of the former category include tea, coffee, and yerba mate; for the latter, certain sodas, as well as energy drinks are common.

Isolated caffeine does not have a particularly strong taste; it is, however, distinctly bitter. Given the high availability and legality of caffeine, it is also possible for caffeine users to obtain the drug and add it to a normally non-caffeinated solution for drinking.

Caffeine can also be obtained over-the-counter in pill form, in medication usually intended to ward off drowsiness, promote alertness (often as a study aid, or for those driving late at night), and to fight tension headaches. (Caffeine is known to have antimigraine and slight analgesic effects.) It can be found in many over-the-counter medications such as No-Doz, Excedrin, Vivarin, and some pain and cold medications.

Caffeine can also be used rectally, and there have been reports of people attempting to smoke or insufflate the drug, with varying degrees of success.

Effects of Caffeine

Caffeine stimulates the central nervous system and metabolism by acting as a nonselective antagonist of adenosine receptors in the brain. The drug binds to the same receptors that adenosine usually would in the brain, inhibiting adenosine from being able to bind to those receptors. The general effects of a 'normal' dose include:
  • decreased fatigue
  • increased metabolism
  • increased feelings of energy
  • physical and psychological stimulation
  • wakefulness, decreased drowsiness
  • increased focus and coordination
  • faster ability to think and react
  • in some people (somewhat paradoxically, and particularly caffeine-tolerant people), increased ability to sleep
  • increased effectiveness of over-the-counter headache medicines when combined

Caffeine has a number of side-effects. Many of these side effects are mild at normal dosages but increase in intensity in a linear fashion with dosage. Likewise, some of these side-effects come from repeated dosing. These side-effects include but are not limited to:
  • restlessness
  • anxiety
  • insomnia
  • lower quality of sleep
  • decreased coordination
  • physical and psychological addiction
  • over-excitement
  • mania
  • increased urination (due to increased levels of ketones in urine)
  • upset stomach
  • irritability
  • rapid/irregular heartbeat
  • increased potential for dehydration
Caffeine is capable of causing both psychological and physical addiction, with withdrawal symptoms in those who are addicted including headaches, irritability, poor concentration, fatigue, drowsiness, insomnia, nausea, stomach pain, and general body pain. These effects usually start within 12-24 hours of the last caffeine usage and continue for up to five days. Even after physical withdrawal symptoms have passed, psychological cravings for caffeine may continue. Given caffeine's high availability and widespread use, as well as the fact that many users may be consuming caffeine without even realizing it, most people have a very hard time preventing themselves from using the drug.

Combinations with Caffeine

As a central nervous system stimulant, caffeine can be dangerous to combine with other stimulants such as amphetamines, MDMA/MDA, cocaine, ephedrine and various other drugs. These drugs, when used together, can cause over-stimulation, and increase the side effects of both stimulants—often causing racing heartbeat, inability to focus, dehydration, and overheating. In more severe cases, these combinations can be fatal.

Caffeine is known to work together with non-steroidal anti-inflammatory drugs (NSAIDs) to increase their efficiency in reducing headaches, due to caffeine's ability to increase blood flow throughout the blood vessels in the brain.

Caffeine can help counteract the effects of CNS depressants, promoting wakefulness and alertness. However, taking a combination of caffeine and a depressant can lead to a greater number of potential side-effects. Alcohol and caffeine can provide for a dangerous combination, as both can cause dehydration. This has led to a recall in the United States of most energy drinks containing alcohol.

Caffeine is often combined with vitamins, nutrients, and various alkaloids which supposedly also provide energy—such as taurine, as well as sugar—in many soft drinks and energy drinks. These products are often marketed to increase energy and ability, particularly in situations which are labor-intensive or require a great deal of energy and/or focus. These products often have notable side effects similar to caffeine and other stimulants but are oftentimes more severe than caffeine alone. Some individuals are more sensitive to the effects of caffeine and the other chemicals contained within these beverages, thus caution is recommended upon using these products.

Although it may affect the experience associated with hallucinogenic drugs such as cannabis and psychedelics, there are no significant physical side-effects that result from the combination of these types of drugs with a normal dose of caffeine. (Not accounting for those who are particularly sensitive to caffeine.) Each individual drug's effects, when combined, however, may change the experience the user has. For instance, caffeine may help a drug user feel more alert during a cannabis high or during a psychedelic or dissociative experience.

Caffeine is generally well-tolerated in moderate dosages when used in combination with other drugs. It is often combined with a host of other drugs by millions of people daily, with few negative side effects noted. However, just like any drug or drug combination, it may affect each individual differently, thus it's important to know how your body will react to a drug or a combination of given drugs at the dosage supplied. Higher doses often increase side effects, which is always something to take into consideration, especially when combining two drugs.

Different Uses for Caffeine

Pharmacology of Caffeine

LD50 (mg/kg) [1] :
Mice : 127 (male), 137 (female) orally
Rat : 355 (male), 247 (female) orally
Hamster : 230 (male), 249 (female) orally
Rabbit : 246 (male), 224 (female) orally

Chemistry of Caffeine

Column 1 Column 2
Systematic (IUPAC) name: 1,3,7-trimethyl-1H-purine-2,6(3H,7H)-dione 3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione
Synonyms: 3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione, 1,3,7-trimethylxanthine, 1,3,7-trimethyl-2,6-dioxopurine, coffeine, thein, guaranine, metyltheobromide, No-Doz; caffeine citrate, citrated caffein, Cafcit (mixture with citric acid)
Molecular Formula: C8H10N4O2
Molar mass: 194.19 g/mol
CAS Registry Number: 58-08-2, 69-22-7 (mixture with citric acid)
Melting Point: 238°C
Boiling Point: no data
Flash Point: no data
Solubility: 1 g dissolves in 46 mL water, 5.5 mL water (80°C), 1.5 mL boiling water, 66 mL alcohol, 22 mL alcohol (60°C), 50 mL acetone, 5.5 mL chloroform, 530 mL ether, 100 mL benzene, 22 mL boiling benzene; freely soluble in pyrrole, tetrahydrofuran containing about 4% water; soluble in ethyl acetate; slightly soluble in petroleum ether. Mixture with citric acid soluble in about 4 parts warm water.
Additionnal data: sublimes at 178°C; fast sublimation at 160-165°C (1 mmHg, 5 mm distance); pH of 1% solution in water 6.9; density (18°C) 1.23
Notes: Aspect : hexagonal prisms obtained by sublimation; odorless with a bitter taste; solubility increased by alkali benzoates, cinnamates, citrates or salicylates. Monohydrate aspect : felted needles, efflorescent in air, complete dehydration takes place at 80°C. Mixture with citric acid aspect : white, crystalline powder

The Dangers of Caffeine

Caffeine can be both physically and psychologically addicting. It can also produce tolerance in its users, requiring more and more caffeine to achieve the same effects.

Symptoms of caffeine withdrawal can include headaches, irritability, concentration issues, drowsiness, insomnia, stomach pain, and cravings for the drug.

Caffeine can be toxic in large doses, acting as a central nervous system stimulant. It can affect heart rate and cause dehydration, and deaths caused by caffeine usually are the result of the effects of the drug on the heart. The drug has a median LD50 of 192mg/kg in rats, however, it is very feasible that this number is lower in humans.

Overdoses of caffeine can be a particularly negative experience, with symptoms such as a racing heart or irregular heartbeat, increased urination due to increased levels of ketones in the urine, restlessness, insomnia, mania, anxiety, stomach disturbances, rambling thought/speech processes, and irritability. These side-effects usually increase in a dose-dependent manner, although those not used to the effects of caffeine may notice these side-effects in doses much lower than those who have gained a tolerance to the drug.

Given the high availability of caffeine, it can be very hard to avoid. Many people do not know that certain products contain caffeine - for instance, it is commonly believed that all root beers are caffeine free, which isn't true as Barq's Root Beer actually contains a decent amount of caffeine. Dr. Pepper has also been claimed to not have caffeine, although it does have quite a modest dosage of the drug. Many people believe that tea doesn't contain caffeine - and though it usually does not contain much, there is usually some caffeine contained in tea, especially green tea. On top of this, people can become dependent on caffeine very easily. It is easy to drink coffee or a soda in the morning to wake yourself up, versus trying to fight to do it naturally, especially in those who have been using caffeine for such purposes for a long period of time.

Producing Caffeine

Caffeine is usually produced biologically by various plant species such as coffee and tea plants, and is subsequently extracted from these plants and added to various drinks, or is consumed as part of a drink made from these plants. It is assumed that caffeine's original function in these plants is to ward off pests, working as a natural pesticide.

Caffeine can also be synthesized. This method of producing caffeine, however, is likely to be much more expensive than naturally obtained caffeine.

Forms of Caffeine

Caffeine is usually found dissolved within various drinks, including coffee, tea, sodas, and energy drinks. However, it can also be found in its pure powdered state, in pills marketed towards promoting energy/alertness, and mixed with other drugs such as NSAIDs for the purposes of alleviating headaches. Given its widespread availability and use, manufacturers have attempted to put caffeine in many common household products as well, an example includes caffeinated soap.
Caffeine is legal to possess, use, buy, sell, and transfer throughout most of the world. One exception may be countries which have very strong religious views, in which the use of any drug is seen as unnatural and is either frowned upon, or is a crime.

It should be noted that driving while intoxicated on caffeine might be punishable in some situations if the driver has clearly consumed so much caffeine that it renders him or her unable to drive safely. Being under the effects of normal amounts of caffeine, however, is a completely acceptable practice while driving. It all comes down to the user, and knowing whether he/she is okay to drive at the time.

United Nations


Caffeine is legal to possess, use, buy, sell, transfer, or transport in the United States of America.


Other Countries

History of Caffeine


  1. ^Merck Index, fifteenth edition (2013)

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