INTRODUCTION
1 . Drug:
- Any externally administered substance that modifies or affects chemical reactions in the body
2 . Drugs can be grouped as follows:
- I. Sedatives (Depressants):
- Slow down the brain and make you feel sleepy;
- Include tranquilizers and sleeping pills;
- e.g. alcohol
- II. Stimulants:
- Speed up the action of the brain and make you feel alert;
- Sometimes given to people who are suffering from severe depression;
- e.g. coffee, tea and nicotine
- III. Hallucinogens:
- Cause a person to experience illusion, hallucinations and distorted images;
- e.g. cannabis
- IV. Opiates:
- Include opium, morphine and heroin;
- Relieve pain and induce sleep and stupor
3 . Drugs may cause:
- I. Tolerance:
- If taken over a long period of time, the dosage has to keep increasing in order to have the same effect;
- If the dosage continues to increase, it will become so large that it may cause death;
- e.g. people who drink alcohol in order to relieve anxiety may have to keep drinking more and more before they feel relaxed
- II. Dependence:
- It is the condition in which the user cannot do without the substance;
- e.g. cigarette smoking can cause emotional dependence – crave for it, may be bad tempered, anxious or depressed without it;
- May also cause physical dependence (addiction) and cause withdrawal symptoms(??)
13.1 Antibiotics
1 . Antibiotics:
- Chemicals that are widely used to treat many infectious diseases caused by microorganisms;
- Produced by certain bacteria and moulds and some are man-made;
- Do not harm viruses
2 . Four main types of anti biotics:
- I) Penicillins:
- Made by the fungus Penicillium;
- Attack a few bacteria (Narrow-spectrum antibiotics)
- II) Cephalosporins:
- Made by the mould Cephalosporium;
- Useful against penicillin-resistant bacteria
- III) Tetracyclines:
- Made by the bacterium Streptomyces aurofaciens;
- Act against a variety of bacteria (Broad-spectrum antibiotics)
- IV) Erythromycins:
- Work against the same type of bacteria as penicillin;
- Useful against penicillin-resistant bacteria
3 . Anaesthatics:
- Drugs that made the body unable to feel pain;
- e.g. Cocaine, which causes a loss of sensation in the area where it is injected
4 . Analgesics:
- Drugs that can relieve pain without causing numbness or affecting consciousness;
- e.g. Aspirin, which relieves minor pain and reduces fever,
- If taken in large doses, may produce some side effects, e.g. gastric ulcers
13.2 Effects of heroin
1 . Heroin:
- Obtained from opium;
- A type of painkillers;
- Used as a sedative and powerful analgesic;
- Highly addictive (drug dependence), often abused by drug users
2 . Effects of heroin:
- Social problems;
- Brain damage (affect the brain);
- Lung damage (affect the lungs);
- Affect the diet – lose of weight, constipation, lose of appetite, gastric ulcers
- Withdrawal symptoms:
- Physically ill (experiences nausea, vomiting, uncontrolled trembling);
- Mentally disturbed (experience acute anxiety, depression, etc.).
13.3 Effects of alcohol
1 . Alcohol:
- A depressant;
2 . Effects of alcohol:
- Slow down some brain functions;
- Reduce nervous tension and worries;
- Self-control is reduced;
- Blurred vision and poor muscular co-ordination;
- Anaesthetize the brain and can cause unconsciousness;
- Addiction (drug dependence).
- Damage the liver because alcohol is broken down in the liver;
- Social problems
13.4 Effects of tobacco smoke
1 . 3 major components of tobacco smoke:
- Nicotine – addictive drug;
- Tar -a brown, sticky substance that accumulates in the lungs during smoking;
- Carbon monoxide (CO).
2 . Effects of nicotine:
- Stimulates the brain making the smoker alert and relaxes the muscles then, dulls the brain and senses;
- Release adrenaline -increase the rate of heartbeat and blood pressure;
- Clots the blood easily -increasing the risk of blood clots blocking the blood vessels -clotting of the coronary arteries cause heart attack, clotting of the capillaries of the brain cause stroke;
3 . Effects of carbon monoxide:
- Reduces the efficiency of the red blood cells to transport oxygen – may cause death;
- Increases the rate of the deposition of fatty substances on the inner walls of arteries, causing lumen to become narrower;
- Damages the lining of blood vessels -increasing the tendency of the blood to clot and so block the blood vessels;
- It is more readily to combine with haemoglobin to form carboxyhaemoglobin instead of oxyhaemoglobin.
4 . Effects of tar:
- Contains cancer-causing (carcinogens) chemicals;
- Uncontrolled multiplication of cells results in outgrowths or lumps of tissue (cancer) -blocking off the air sacs, reducing the efficiency for gaseous exchange;
- Paralyses the cilia from removing dust particles from the lungs and trachea.
5 . Smoking-related diseases:
- Lung cancer;
- Chronic brochitis;
- Emphysema
6 . Effects of smoking during pregnancy:
- Brain development of the fetus is affected -the child may have learning difficulties in later life;
- The fetus grows more slowly, born smaller, more fragile and may die quickly within the first few days of life;
- A higher risk of the baby being born prematurely;
- The baby has a greater risk of being born dead (stillborn).
7 . Nowadays,many people regard smoking as no longer socially acceptable.