Caffeine

Brewed coffee, raw coffee beans and caffeine powder

Caffeine is a naturally occurring stimulant, which is unique from most other psychoactive drugs in that it is almost ubiquitously legal and in heavy use worldwide. Ordinary use of the caffeine has a low risk of causing health problems, though many modern cultures engage in a 'caffeine culture' which involves heavy regular use and arguable dependence on the drug.

History

Caffeine has been used by humans for thousands of years recreationally. The first documented use of caffeine was in China during 3000 BCE in the form of tea.

Records of coffee use appear somewhat later, around the 15th century in Arabia, from where it spread to Egypt and Africa - later reaching Italy, wider Europe and the rest of the world.

Caffeine as a distinct chemical was first isolated in 1819 in Germany, later being independently isolated in 1821 by French and Swedish scientists both. However, it wasn't until 1895 caffeine was first synthesised.

Usage

The most common consumption method is in a brewed drink (such as tea or coffee) or in a carbonated beverage, such as soda. Caffeine is also found in several foods, namely chocolate, and can be eaten in capsule or pill form. It can also be bought as a powder, usually in bulk.

When imbibed as a brewed drink, the caffeine is usually derived from the natural content existing in the produce of the coffee plant or tea bush.

It is most commonly used for its properties of mental and physical stimulation, being consumed throughout the day increase concentration and wakefulness. Along with personal use, it is in common use at workplaces throughout the world. There is also a huge industry in shops which exist with the express purpose of selling caffeinated beverages.

Dosage

The average cup of coffee contains between 90 and 200mg of caffeine. A coca-cola contains on average between 25 and 35mg of caffeine. A cup of black tea averages 14 to 70mg of caffeine. Note: While it's difficult to state specific values for brewed drinks due to the variety of preparation methods, these are the most commonly found values.

Oral

Threshold	10-20mg
Light	20-150mg
Common	150-250mg
Strong	250-400mg
Heavy	400mg+
Lethal	3 Grams+

Duration

Note: Duration can be significantly longer with higher doses.

Oral

Onset	5-10 minutes
Total	1.5-5 hours

Effects

In higher doses, caffeine can cause panicked thinking, racing thoughts, and an uncomfortable bodyload. With ordinary use, people tend to experience little to no after-effects from caffeine alone.

Positive

• Stimulation

• Mild Euphoria

• Increase in cognitive abilities

• Increased drive

• Increased focus

Neutral

• Basal metabolic rate increase

• Decreased appetite

• Increased perspiration

• Respiratory rate increase

• Heart rate increase

• Diuretic effects

Negative

• Anxiety

• Jitters

• Feelings of discomfort

After effects

• Tiredness (crash)

• Irritability

Harm Reduction

See also information under Stimulants.

• Regular use of caffeine can cause dependence and withdrawal, which can last between 3-12 days.

• Binging on caffeine may cause symptoms of a more general stimulant comedown. See Quick Guide to Stimulant Comedowns for more.

Interactions

Ordinary amounts of caffeine are usually relatively safe in combination with most drugs, however many users find the combination of caffeine with other drugs that stimulate the CNS to be quite uncomfortable.

See the Drug combinations chart for more information.

Chemistry and Pharmacology

Caffeine is part of the class of substances called "Xanthines"

Caffeine's mechanism of action is mostly through the adenosine receptor (Antagonist at all of them) Which causes the stimulation.

Since Caffeine is both lipid and water soluble it crosses the blood brain barrier with ease.

LD50

190 milligrams per kilogram

Legal status

Caffeine is legal in most of the world, though as a psychoactive chemical is usually regulated to some degree; usually occurring in a limit on the amount of caffeine content a product can legally contain.