Caffeine is a drug found in coffee, tea, chocolate and cola. It is a stimulant drug because it speeds up the functions of the central nervous system.
Forms and Appearance
In its pure form, caffeine is a white powder.
Medical and Other Uses
Caffeine is used, in combination with other drugs to treat migraine headaches, and also as a mild stimulant.
Caffeine is often used as an ingredient in stimulants sold on the street, and is sometimes marketed as more powerful stimulants such as amphetamines.
Methods of Use
As a medicine, caffeine is usually given orally in tablets or capsules, or injected. Abusers sometimes inject it intravenously. Most people drink it in coffee, tea or cola drinks, or eat it in chocolate.
Guide to strengths
- Instant coffee: 60-100mg per cup
- fresh coffee: 80-350mg per cup
- decaffeinated coffee: 2-4mg per cup; tea: 8-90mg per cup
- cola drinks: 35mg per 250ml
- cocoa and hot chocolate: 10-70mg per cup
- chocolate bars: 20-60mg per 200g bar
- some prescription and over the counter medicines such as NO DOZ and some cough, headache and slimming preparations: 20-100mg per dose.
Most researchers agree that there is very little health risk when less than 600mg of caffeine is consumed a day.
Many doctors recommend less than 200mg a day (approx 2-4 cups of coffee or tea) if the person is suffering anxiety or stress, or is pregnant.
Effects of Use
The immediate effects of caffeine include: increased alertness, metabolism and body temperature. Caffeine also stimulates the secretion of gastric acid and increases urination. Caffeine taken before going to bed can also delay and shorten sleep.
People use caffeine for a number of reasons:
• to stimulate thinking
• to keep awake
• to suppress appetite
• and to improve alertness and quicken reaction time
In large doses, caffeine can produce headaches, jitters, nervousness and even delirium. This is especially so for someone not used to taking caffeine. Drinking or eating more than 10g of caffeine can produce high blood sugar and urinary acid levels. (Note that 10g of caffeine is equivalent to 30 cups of strong freshly brewed coffee.)
Tolerance, Dependence and Withdrawal
Tolerance does not seem to develop. Users do not seem to need to increase the amount of coffee they drink to achieve the same effects. However, having coffee before bed is more likely to cause insomnia in people who don’t usually drink coffee than in regular coffee drinkers.
People can become dependent on caffeine. If caffeine is unavailable they may panic or feel anxious. People who are dependent on caffeine may experience withdrawal symptoms such as headaches, irritability and a feeling of tiredness if they stop or dramatically cut down their caffeine intake.
Deaths from overdose of caffeine are very rare. However, it is possible if large doses are taken orally or injected intravenously.