Caffeine AUSTRALIAN DRUG FOUNDATION
15 HOW DRUGS AFFECT YOU
This pamphlet is part of the “How Drugs Affect You� series. It aims to provide the facts about caffeine for anyone interested in understanding more about this drug. It has been written for the general public, including employees, employers, health professionals and their clients.
Other titles in this series include alcohol, amphetamines, analgesics, benzodiazepines, cannabis, cocaine, drugs and their effects, ecstasy, GHB, hallucinogens, heroin, ice, inhalants, ketamine and tobacco.
15 HOW DRUGS AFFECT YOU
What is caffeine? Caffeine is a drug found in the leaves, seeds or fruit of a number of plants such as coffee and tea. Caffeine is also manufactured and added to foods, drinks and medicines. It can be found in coffee, tea, chocolate, and some soft drinks. It is also used in prescription and over-the-counter medicines to treat tiredness or drowsiness and to improve the effect of some pain relievers. It is a mild stimulant drug — meaning that it speeds up messages going between the body and the brain.
What it looks like In its pure form, caffeine is an odourless, bitter tasting silky white powder.
Sources of caffeine Coffee Coffee beans are the seeds of the coffee plants Coffea arabica, Coffea canephora and Coffea liberica. The amount of caffeine in coffee beans depends on the variety of the plant. Different serves of coffee (e.g. cappuccino, short black) can contain different amounts of caffeine. Tea There are many types of tea plant (Camellia sinensis). Two varieties — Camellia sinensis assamica and Camellia sinensis sinensis — produce most of the caffeinated tea consumed worldwide. Kola nut Kola nut is the caffeine-containing nut of Cola acuminata and Cola nitida trees of the cocoa family (Sterculiaceae), which grow in Africa. It is mainly used as an ingredient in soft drinks and medicine. Cacao pod The seed pod of the cacao pod (Theobroma cacao) contains caffeine and is used to make cocoa and chocolate products. Caffeine tablets Caffeine tablets such as No-Doz® are used to keep a person awake and alert when they are feeling tired or drowsy. They contain approximately 100 mg of caffeine or about the same amount as a cup of coffee. Many caffeinated products are also available un-caffeinated (no caffeine is added) or decaffeinated (any caffeine present is reduced or removed).
How is it used? Caffeine is most commonly consumed in the form of a drink such as coffee, tea or a soft drink. It can also come in the form of a pill and can be eaten in food such as chocolate.
Caffeine statistics According to the Australian Coffee Traders Association,1 in 2006:
»» one billion cups of coffee per year were consumed
at cafés, restaurants and other outlets in Australia
»» consumption of coffee has doubled over the past 30 years from 1.2 to 2.4 kg per person.
While there is currently no Australian equivalent recommendation, the suggested average intake of caffeine for Canadians is approximately 400 mg per day2.
Caffeine content in common foods and drinks Drink/product
Size/amount
Coffee »» Instant
Caffeine content (mg)
250 ml
80–120
»» Drip/percolated
250 ml
150–240
»» Espresso
250 ml
105–110
»» Decaffeinated
250 ml
2–6
Tea (medium-strength)
250 ml
65–105
Coca Cola
375 ml
49
Pepsi
375 ml
40
®
®
Red Bull energy drink
250 ml
80
Mother® energy drink
500 ml
160
Iced coffee drink
500 ml
30–200
Hot chocolate
250 ml
5–10
Milk chocolate
55 g
3–20
Dark chocolate
55 g
40–50
No Doz
1 tablet (Aus)
100
®
(commercial brands)
®
Australian Coffee Traders Association website 2006 “Australian coffee stats”, at www.acta.org.au/article.php?a=2 (accessed 31/08/11).
1
2
Healthy Canadians website 2011 “Kids and caffeine”, at www.healthycanadians.gc.ca/init/kids-enfants/food-aliment/nutrition/caf/ index-eng.php (accessed 31/08/11).
The caffeine content of tea and coffee varies widely, depending on the brand, the way that the individual makes their beverage, and the size of their mug or cup.
Effects of caffeine The effects of any drug (including caffeine) vary from person to person. How caffeine affects a person depends on many things including their size, weight and health, also whether the person is used to taking it and whether other drugs are taken around the same time. The effects of any drug also depend on the amount taken.
Immediate effects After being consumed, caffeine takes around 5–30 minutes to travel around the body. The effects of caffeine can last up to 12 hours. Some of the immediate effects of caffeine are:
»» reduced fatigue »» increased mental
alertness »» increased heart rate »» increased stomach acid.
See diagram
»» increased need for urination
»» increased body temperature
Psychological effects » elevated mood » increased mental alertness » increased performance in simple tasks » increased energy » increased concentration » increased attentiveness » reduced drowsiness and fatigue
Brain » stimulation of the brain » constriction of blood vessels (relieving some types of headaches)
Body » muscle twitches » increased stimulation of the nervous system
Bladder increased need for urination
Stomach » ache » nausea » short-term reduction in appetite
Heart » small increase in heart rate » slight increase in blood pressure
Mouth » dry mouth » thirst
Eyes slightly enlarged (dilated) pupils
Low to moderate doses
Higher doses A high dose of caffeine can cause a person to overdose. This means that a person has taken more caffeine than their body can cope with. Higher doses of caffeine can produce symptoms, including:
»» irritability »» restlessness »» nervousness »» flushed face »» insomnia »» tremors and
muscle twitches
Very high doses
»» mild delirium »» anxiety »» vomiting
»» rambling flow of
thoughts and speech
»» rapid and irregular heartbeat »» unintentional fidgeting (such as pacing up and down or continuous wringing of the hands).
»» seizures »» muscle tension »» abnormal heart rate.
Long-term effects Long-term effects of caffeine use may include:
»» restlessness »» nervousness »» excitement »» insomnia »» flushed face
»» increased need for urination
»» rapid and irregular heartbeat
»» agitation.
Most people can consume up to 300 mg of caffeine (about four average cups of coffee) daily without any adverse effects. However, some people are more sensitive to caffeine than others and taking a small amount may bring about effects such as restlessness and insomnia. Tolerance and dependence Over time and with frequent use, people can become used to functioning with caffeine in their body. They can become psychologically or physically dependent on caffeine. People who use small to moderate doses of caffeine may experience little or no harm. However, evidence shows that as little as 100 mg of caffeine a day (equal to about one energy drink or one cup of strong coffee) can cause dependence in some people. Withdrawal symptoms are likely to occur when a person dependent on caffeine tries to stop using it.
Withdrawal If a dependent person stops taking caffeine, they may experience withdrawal symptoms because their body has to get used to functioning without caffeine. Symptoms can begin within 12–24 hours after last use and can last approximately 7 days. Consuming caffeine will stop the symptoms. Health professionals recommend gradually reducing caffeine intake rather than stopping abruptly. Some of the withdrawal symptoms that may be experienced include:
»» headaches »» drowsiness »» fatigue
»» decreased alertness »» decreased activity »» cravings for caffeine.
Caffeine overdose Death or serious injury from a caffeine overdose can occur, but it is extremely rare. To suffer an overdose, a person would need to consume 5–10 g of caffeine (about 80 cups of strong coffee one after the other). Some of the effects of caffeine overdose are:
»» involuntary shaking (tremors) »» nausea and vomiting »» irregular or rapid heart beat »» panic attack and confusion »» seizure. Small children can experience caffeine overdose after consuming smaller amounts such as up to 1 g (equal to around 12 energy drinks).
Caffeine and driving It can be dangerous to drive after having a large dose of caffeine. The effects of large doses of caffeine such as restlessness, nervousness and excitement can affect driving ability. Rambling thoughts and mental agitation can cause a driver to take chances that they might not otherwise take which can increase the chance of an accident.
Caffeine and the workplace Under occupational health and safety legislation, all employees have a responsibility to make sure they look after their own and their co-workers’ safety. The effects of high doses of caffeine such as anxiety and mild delirium can affect a person’s ability to work safely and effectively.
Pregnancy and breastfeeding Pregnant women who consume high amounts (more than 600 mg per day) of caffeine are at increased risk of difficult birth, early labour, miscarriage and birth of low-weight babies. Research has found that neonatal withdrawal symptoms such as rapid breathing, fast and irregular heartbeat and tremors have occurred in babies born to mothers who consume large amounts of caffeine. If a mother uses caffeine while breastfeeding, it will be present in her breast milk. If you are planning to drink coffee during your pregnancy or while breastfeeding, check with your doctor or other health professional.
Caffeine and other drugs The effects of mixing caffeine—a stimulant—with other drugs, including over-the-counter or prescribed medications, can be unpredictable and dangerous. Always read the instructions or seek advice from a health professional before mixing caffeine with medications. Stimulants such as caffeine can mask some of the effects of alcohol. For example, if a person combines alcohol with energy drinks they may still become intoxicated by the alcohol but not feel as relaxed or sleepy. This can lead them to taking more risks and being more likely to experience alcohol-related harm such as being injured in a fight or accident.
Preventing and reducing harms Many Australians take at least one psychoactive drug on a regular basis— they might take medication (i.e. over-thecounter or via a prescription), drink coffee, drink alcohol, smoke tobacco or use an illegal drug. All drugs have the potential to cause harm. As use increases, so does the potential for harm. Australia’s national drug policy is based on harm minimisation. Strategies to minimise harm include encouraging people to avoid using a drug through to helping people to reduce the risk of harm if they do use a drug. It aims to reduce all types of drug-related harm to both the individual and the community.
There is no safe level of drug use Use of any drug always carries some risk—even medications can produce unwanted side effects. It is important to be careful when taking any type of drug.
What to do in a crisis If someone overdoses or has an adverse reaction while using caffeine, it is very important that they receive professional help as soon as possible. A quick response can save their life.
»» Call an ambulance. Dial 000. »» Stay with the person until the ambulance arrives. Find out if anyone at the scene knows cardiopulmonary resuscitation (CPR). »» Ensure that the person has adequate air by keeping crowds back and opening windows. Loosen tight clothing. »» If the person is unconscious, don’t leave them on their back—they could choke. Turn them on their side and into the recovery position. Gently tilt their head back so their tongue does not block the airway. »» If breathing has stopped, apply CPR. »» Provide the ambulance officers with as much information as you can—such as how much caffeine was taken, how long ago and any pre-existing medical conditions.
For further tips on how to reduce the risks of using caffeine, call the alcohol and drug information service in your state or territory. The telephone numbers are listed on the back of this pamphlet.
Caffeine
For information, counselling or other assistance, contact the alcohol and other drug service in your state or territory. AUSTRALIAN DRUG FOUNDATION
ACT (02) 6207 9977
Tas. 1800 811 994
NSW (02) 9361 8000 (Sydney) 1800 422 599 (NSW)
Vic. 1300 85 85 84 (information)
NT 1800 131 350
QLD 1800 177 833 SA
1300 131 340
1800 888 236 (counselling)
WA (08) 9442 5000 (Perth) 1800 198 024 (WA)
Produced by the Australian Drug Foundation Š 2011. Celebrating more than 50 years of service to the community, the Australian Drug Foundation is Australia’s leading body committed to preventing alcohol and other drug problems in communities around the nation. www.adf.org.au For further copies of this pamphlet: Post: PO Box 818 North Melbourne Vic 3051 Street: 409 King Street West Melbourne Vic 3003 Email: druginfo@adf.org.au Web: www.druginfo.adf.org.au
15 HOW DRUGS AFFECT YOU