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Tobacco
Australian Drug Foundation © 2005
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This information has been adapted from the pamphlet How Drugs Affect You: Tobacco, produced by the Australian Drug Foundation. For single copies of this pamphlet contact the DrugInfo Clearinghouse on telephone 1300 85 85 84 or email druginfo@adf.org.au (Victoria only). Multiple copies are available through the ADF Bookshop.
What is tobacco?
Tobacco comes from the leaves of the tobacco plant (Nicotiana tabacum and Nicotiana rustica), which contain nicotine. Nicotine is a stimulant drug. Stimulant drugs act on the central nervous system to speed up the messages travelling between the brain and the body.
The leaf of the tobacco plant is dried, cured and aged before having other ingredients added to manufacture a range of tobacco-based products. For example, cigarettes (including some herbal cigarettes), cigars, pipe tobacco, chewing tobacco, and wet and dry snuff.
What's in cigarette smoke?
There are more than 4000 chemicals in tobacco smoke. Many of these chemicals are poisonous and at least 43 of them are carcinogenic (cause cancer). The three major chemicals in tobacco smoke are:
- Nicotine—the chemical on which smokers become dependent
- Tar—which is released when a cigarette burns
- Carbon monoxide (CO)—a colourless, odourless and very toxic gas that is taken up more readily by the lungs than oxygen. Smokers typically have high levels of CO in the blood.
Effects of tobacco smoke
Tar in cigarettes coats the lungs and can cause lung and throat cancer in smokers. It is also responsible for the yellow–brown staining on smokers' fingers and teeth.
Carbon monoxide in cigarettes robs the muscles, brain and blood of oxygen, making the whole body—especially the heart—work harder. Over time this causes airways to narrow and blood pressure to rise, and can lead to heart attack and stroke. High levels of CO, together with nicotine, increase the risk of heart disease, hardening of the arteries and other circulatory problems. A first-time smoker will often feel dizzy and sick.
"Light" or "low tar" cigarettes
Research has shown that there is little difference between the amount of chemicals inhaled by people who smoke "light" or "low tar" cigarettes and those who smoke regular cigarettes. People who smoke "light" cigarettes have the same risk of developing smoking-related diseases as people who smoke regular cigarettes.
Immediate effects
Soon after smoking tobacco, the following effects may be experienced:
- initial stimulation, then reduction in brain and nervous system activity
- enhanced alertness and concentration
- mild euphoria
- feelings of relaxation
- increased blood pressure and heart rate
- decreased blood flow to body extremities like the fingers and toes
- dizziness, nausea, watery eyes and acid in the stomach
- decreased appetite, taste and smell.
Overdose
Although rare, it is possible to overdose on the nicotine in tobacco.
Very large doses of nicotine can result in an increase in the unpleasant effects, including feelings of faintness and confusion, and a rapid decrease in blood pressure and breathing rate.
In some cases, it can lead to convulsions and death from respiratory failure. Sixty milligrams of nicotine taken orally can be fatal for an adult.
Long-term effects
It is estimated that more than 140 000 hospital episodes and 19 000 deaths in Australia can be attributed to tobacco use every year. The principal diagnoses are cancer, heart disease and chronic obstructive pulmonary disease.
Passive smoking
Passive smoking can cause a number of health problems including heart disease, lung cancer and irritation of the eyes and nose. It involves breathing in tobacco smoke from other people's cigarettes: smoke that has been exhaled or smoke from the end of a lit cigarette.
50 Australians die every day from smoking, compared to 10 who die from alcohol-related conditions and four who die as a result of road accidents.
Tolerance and dependence
People who use tobacco tend to develop a tolerance to the effects of the nicotine in the tobacco very quickly. This means they need to smoke more and more in order to get the same effect.
With repeated use of tobacco, the risk of dependence on nicotine is high. Dependence on nicotine can be physiological, psychological or both.
People who are physically dependent on nicotine find their body has become used to functioning with the nicotine present and may experience withdrawal symptoms when they reduce their nicotine intake.
People who are psychologically dependent on nicotine may find they feel an urge to smoke when they are in specific surroundings, such as at the pub, or in particular situations such as during their lunch break or socialising with friends.
Research has shown that smoking is often associated with different roles and meanings for smokers, including:
- social roles—such as enjoyment of the company of friends, the drinking of coffee or alcohol, and promoting social confidence and feelings of independence (particularly for young women)
- emotional roles—caring for the self, such as helping to deal with stress and anxiety, weight control and providing "companionship"
- temporal roles—such as connecting the flow of events or time in the smoker's day, providing a break from work or activities and relieving boredom.
This may be why smoking is sometimes referred to as the most difficult drug to give up.
Withdrawal
If a person who is dependent on the nicotine in tobacco suddenly stops using it or reduces the amount they use, they will experience withdrawal symptoms because their body has to readjust to functioning without the drug.
Most of these symptoms will disappear within days or weeks of quitting smoking, but cravings may persist for years after stopping using tobacco.
Symptoms include:
- cravings
- irritability, agitation, depression and anxiety
- insomnia and disturbed sleeping patterns
- increased appetite and weight gain
- restlessness and loss of concentration
- headaches
- coughing and sore throat
- body aches and pains
- stomach and bowel upsets.
Pregnancy and breastfeeding
Smoking tobacco can affect fertility in both males and females.
Nicotine, carbon monoxide and many other chemicals found in tobacco smoke are passed on to the baby through the placenta. These substances can reduce the amount of oxygen available in the mother's blood, which reduces the amount of oxygen available to the baby. This and the effects of the other chemicals found in tobacco smoke can affect the baby's growth and development, increasing the risk of low birth weight, premature birth and spontaneous abortions.
Babies whose parents smoke also have an increased risk of sudden infant death syndrome (SIDS). They are more likely to suffer from asthma and other respiratory infections than babies of non-smokers.
Nicotine and many of the other substances in tobacco smoke are passed through breast milk to the baby. These substances can reduce the supply of breast milk. Smoking just before breastfeeding may also delay the milk "let down" process.
Quitting tobacco
Quitting tobacco is more effective if tailored to suit a person's circumstances.
Methods include:
- going "cold turkey"
- nicotine replacement therapy (such as transdermal patches, gum, lozenges, inhalers, nasal sprays and sublingual tablets)
- other pharmacotherapies such as bupropion (Zyban SR)
- individual counselling or advice
- support groups
- alternative therapies, such as acupuncture and hypnosis.
Although most people who try to quit smoking do so without assistance, research generally shows that quitting rates improve with assistance. A combination of methods tends to improve a person's chances of quitting; for example, combining nicotine replacement therapy and behavioural assistance.
For more information and support in quitting tobacco, contact Quit on tel. 13 7848 or see your doctor or other health professional.
Benefits of quitting
After a person stops smoking:
- Almost all the nicotine is out of their system after 12 hours.
- The level of carbon monoxide in their blood is reduced and they will have more oxygen in their bloodstream after 24 hours.
- Most of the nicotine by-products are out of their system after five days.
- Their sense of taste and smell will have improved after a couple of days.
- Their blood pressure returns to its normal level within a month.
- Their immune system starts to show signs of returning to normal within a month.
- Blood flow to their hands and feet has improved within three months.
- After a year, the increased risk of dying from heart disease is half that of a person who has continued to smoke tobacco.
Remember, there is no safe level of tobacco smoking.
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