Drugs.docx

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

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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

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III. Hallucinogens: Cause a person to experience illusion, hallucinations and distorted images; e.g. cannabis

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IV. Opiates: Include opium, morphine and heroin; Relieve pain and induce sleep and stupor

3 . Drugs may cause:    

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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;

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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)

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II) Cephalosporins: Made by the mould Cephalosporium; Useful against penicillin-resistant bacteria

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III) Tetracyclines: Made by the bacterium Streptomyces aurofaciens; Act against a variety of bacteria (Broad-spectrum antibiotics)

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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:

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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:

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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