Caffeine

**Caffeine** is a central nervous system (CNS) stimulant drug. It is found in parts of plants, for example tea leaves and coffee beans. Its artificial form is also used in some soft drinks and energy drinks. It is the world's most popular psychoactive drug, and is legal in all of the world, and is most often taken in a drink.

## Sources

Caffeine is naturally found in the fruits, leaves and beans of coffee, cacao, guarana and tea plants.

The plants use caffeine as a _pesticide_. This is a chemical that kills insects if they eat the plant. It is the way the plant protects itself.

Caffeine was first extracted from cocoa beans into its purest form which is a white powder and the word originated from the German word “Kaffee” and the French word “café” which both mean caffeine.

When it comes from the guarana plant it is called **guaranine,** when it comes from a tea plant, it is called **theine,** and in the mate drink it is called **mateine** (this drink is an infusion made with Yerba mate).

## What caffeine is

Caffeine is a _stimulant_ drug. A stimulant is a drug that increases body actions like heart rate, blood pressure, and metabolism. It makes a person more awake and alert.

Caffeine also is a diuretic. This means it makes a person make more urine (the waste liquid a person makes).

The caffeine chemical is called a _xanthine alkaloid_. This is a group of chemicals that are stimulants. Some xanthine alkaloids (like theophylline) are used to help asthma.

## What caffeine is used for

The biggest use of caffeine is as a stimulant. People drink coffee and other drinks with caffeine to stay awake.

In the beginning caffeine was found to relieve hunger, so it was used for weight loss. That did not last because people were using too much. Caffeine can be dangerous when not used in the right way.

Doctors sometimes use caffeine as a medicine. It is added to analgesics (drugs used for pain). This can improve their effect on headaches and other pain. It is sometimes used to help premature babies (babies born very early) to breathe. The short-term risk of this treatment seems to be that the babies treated gain less weight than usual. Caffeine is sometimes given to people after a lumbar puncture. This is when a needle is pushed between the bones of the lower back, normally to check for illnesses like meningitis.

## Problems with caffeine

The largest problem with caffeine is addiction. This is when people get bad symptoms when they do not have the drug. When people have _withdrawal_ (feel bad because they do not have the drug) they drink more. This makes them feel better. But if they cannot get more, they are likely to feel some of the symptoms listed below:
- Headaches
- Being tired or need to sleep
- Caffeine can prevent sleep and in the long-term alters brain functions
    - Sleep deprivation leads to a weakened connectivity between the amygdala and medial prefrontal cortex which regulate mood and emotion.
        - This causes the consumer to feel irritable, tired, restlessness, and anxious.
- Nausea (feeling like vomiting)

Caffeine can also hurt people if they drink a lot at once. If a person consumed 10-13 grams of caffeine quickly, between 80 and 100 cups of coffee, they would overdose and may even die. Caffeine overdose is a medical diagnosis. It is called: _Caffeine-Induced Organic Mental Disorder_ or _Caffeine Intoxication_. People with this can have these symptoms:
- Very bad feelings like:
    - _Paranoia_ (feeling as if people are about to hurt the person)
    - _Restlessness_ or _nervousness_ (with the person feeling like he cannot sit down or rest)
    - _Anxiety_ (very bad worry)
- Muscle movements that cannot be stopped
- Very fast heart rate
- Abnormal heart rhythms (even heart stopping)
- Very high blood pressure
- Vomiting
- Confusion (not knowing who the person is or where they are)

## Caffeine helps for

Caffeine also has some strong advantages:
- Lower risk of coronary disease
- Cut stroke risk
- Speed up metabolism
- Increases memory
- Helps ward off Alzheimer’s
- Reduces kidney stone risk

## How much caffeine is safe

250–300 mg of caffeine a day is a _moderate_ amount. That is as much caffeine that is in three cups of coffee (8oz each cup). More than 750–1000 mg a day is a significant amount, but is very unlikely to kill someone. The Lethal Dose 50 of caffeine is 192 mg per kilogram, in rats. In humans, it is between 150 and 200 mg per kilogram (70-90 per pound.)

Caffeine is in many drinks and foods. This is _approximate_ amounts of caffeine in some food and drink:

- Brewed coffee – 40 to 220 mg in a cup
- Instant coffee – 30 to 120 mg in a cup
- _Decaffeinated_ coffee (with most caffeine taken out) – 3 to 5 mg in a cup
- Tea – 20 to 110 mg in a cup
- Soda drinks with caffeine – 36 to 90 mg in 12 ounces. Some people think that soft drinks which are light in color do not contain caffeine. This is not always true.
- Milk chocolate – 3 to 6 mg in an ounce
- Bittersweet chocolate – 25 mg in an ounce

One ounce – abbreviated oz – is 30 ml.

A 'cup' is 8 oz (240 ml.)

## Different ways to get 200mg of caffeine

|Caffeine equivalents|
| --- |
|In general, each of the following contains approximately 200 milligrams of caffeine: <div class="toccolors" style="-moz-column-count:2; column-count:2;"> * **One** 200 milligram caffeine pill * **One** 2.5 fluid ounce Upshot energy shot (75 millilitres). * **One** 12 fluid ounce cup of regular Starbucks coffee (355 millilitres) Pike Place – 235 mg  Blonde Roast – 270 mg * **One and a half** pounds of milk chocolate<sup>[a]</sup> (680 grams) * **Two** 8 fluid ounce containers of regular coffee (470  millilitres) * **Five** 1 fluid ounce shots of espresso from robusta beans (150 millilitres) * **Eight and a half** 8 fluid ounce cups of Coca-Cola Classic (68 fl oz is approximately 2.0 litres) * **Ten** 8 fluid ounce cups of green tea<sup>[b]</sup> (2.4 litres) * **Fifty** 8 fluid ounce cups of decaffeinated coffee (12 litres) </div> Notes: A _fluid ounce_ is between 28 and 30 millilitres. a. There may also be large amounts of other chemicals, similar to caffeine in chocolate and other products of cacao. There is theobromine in cacao, for example. These substances can have effects similar to those of caffeine. b. Most tea drunk in North America is not very strong. The figures  are for this kind of tea. The tea drunk in most other places of the world is stronger; for these kinds of tea, the figures are probably too small.|

### Scientific information

- eMedicine Caffeine-Related Psychiatric Disorders
- The Consumers Union Report on Licit and Illicit Drugs, Caffeine-Part 1 Part 2
- _The Physician and Sportsmedicine_: Caffeine: A User's Guide
- Caffeine: Psychological Effects, Use & Abuse
- Caffeine Withdrawal Recognized as a Disorder
- Is Caffeine a Health Hazard?

### Others

- Caffeine Withdrawal Symptoms
- Caffeine: How Stuff Works
- Caffeine: The most popular psychoactive drug, Broke but Shredded, January 2022
- Erowid Caffeine Vaults
- #caffeine! - The Caffeine Information Archive
- Naked Scientists Online: Why do plants make caffeine?
- Alcohol and Drugs History Society: Caffeine news page
- Coffee: A Little Really Does Go a Long Way, NPR, September 28, 2006
- Does coffee really give you a buzz? by John Triggs in the Daily Express April 17 2007
- Burgower, Rachael. “The Effects of Energy Drinks on Sleep and Daily Functioning.” , 2014, pp. 1–59.

### News

- National Post: Caffeine linked to psychiatric disorders

## Infobox (drug)

- **image**: Caffeine structure.svg
- **alt**: 2D structure of caffeine
- **image2**: Caffeine molecule ball from xtal (1).png
- **alt2**: 3D structure of caffeine
- **pregnancy au**: A
- **legal uk**: GSL
- **legal us**: unscheduled
- **legal ca**: unscheduled
- **dependency liability**: Physical dependence, Physical: low–moderate

Psychological dependence, Psychological: low
- **addiction liability**: Low / none
- **routes of administration**: Oral route, By mouth, Insufflation (medicine), insufflation, coffee enema, enema, Suppository, rectal, intravenous
- **class**: Stimulant
- **atc prefix**: N06B
- **atc suffix**: C01
- **atc supplemental**: ,
- **onset**: ~1 hour
- **bioavailability**: 99%
- **protein bound**: 25–36%
- **metabolism**: Primary: CYP1A2
Minor: CYP2E1, CYP3A4,
CYP2C8, CYP2C9
- **elimination half-life**: Adults: 3–7 hours
Infants (full term): 8 hours
Infants (premature): 100 hours
- **excretion**: Urine (100%)
- **duration of action**: 3–4 hours
- **metabolites**: Paraxanthine (84%)
Theobromine (12%)
Theophylline (4%)
- **cas number**: 58-08-2
- **pubchem**: 2519
- **drugbank**: DB00201
- **chemspiderid**: 2424
- **unii**: 3G6A5W338E
- **kegg**: D00528
- **chebi**: 27732
- **chembl**: 113
- **pdb ligand**: CFF
- **iuphar ligand**: 407
- **synonyms**: Guaranine
Methyltheobromine
1,3,7-Trimethylxanthine
7-methyltheophylline Theine
- **iupac name**: 1,3,7-Trimethylpurine-2,6-dione
- **c**: 8
- **h**: 10
- **n**: 4
- **o**: 2
- **smiles**: CN1C=NC2=C1C(=O)N(C(=O)N2C)C
- **stdinchi**: 1S/C8H10N4O2/c1-10-4-9-6-5(10)7(13)12(3)8(14)11(6)2/h4H,1-3H3
- **stdinchikey**: RYYVLZVUVIJVGH-UHFFFAOYSA-N
- **density**: 1.23
- **melting point**: 235
- **melting high**: 238
- **melting notes**: (anhydrous)