1 Chapter 35Drugs 35.1Introducing drugs 35.2Anti-acids 35.3Analgesics 35.4Problems with drugs...
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Transcript of 1 Chapter 35Drugs 35.1Introducing drugs 35.2Anti-acids 35.3Analgesics 35.4Problems with drugs...
1
Chapter 35 Drugs
35.1 Introducing drugs
35.2 Anti-acids
35.3 Analgesics
35.4 Problems with drugs
35.5 Hazards of cigarette smoking
CONTENTS OF CHAPTER 35
35.6 Working towards a smokeless Hong Kong
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35.1 INTRODUCING DRUGS
35.1 INTRODUCING DRUGS
MEDICINES AND DRUGS
Medicines are substances used to cure or prevent diseases. Most
medicines consist of one or more drugs.
A drug is a substance which changes the state or function of the
human body.
Alcohol, Milk of Magnesia, aspirin and penicillin are common
examples.
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COMMON TYPES OF DRUGS
Drugs fall into a number of types.
Anti-acids
The word anti-acid means ‘opposite to acid’, often abbreviated as
antacid.
Anti-acids relieve stomach trouble. They act by neutralizing
excess acid in the stomach.
35.1 INTRODUCING DRUGS
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Figure 35.2
Milk of magnesia is an
anti-acid.
35.1 INTRODUCING DRUGS
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Analgesics
Analgesics are painkillers, that is, they relieve pain.
35.1 INTRODUCING DRUGS
Figure 35.3 Panadol is an analgesic.
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35.1 INTRODUCING DRUGS
Antibiotics
Antibiotics are used to treat bacterial infections.
Figure 35.4 Keflex is an antibiotic.
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Anti-histamines
Anti-histamines are used to treat allergy. They are effective in
relieving hay fever and allergic rashes.
Figure 35.5 Polaramine is an anti-histamine.
35.1 INTRODUCING DRUGS
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Hypnotics
Hypnotics cause sleepiness.
Figure 35.6 Barbiturates are hypnotics.
35.1 INTRODUCING DRUGS
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Tranquillisers
Tranquillisers are substances which relieve tension and anxiety.
Figure 35.7 Valium is a tranquilliser.
35.1 INTRODUCING DRUGS
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A35.1
Penicillin is an effective antibiotic. It has saved many lives from
bacterial infections since the 1940s.
35.1 INTRODUCING DRUGS
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35.2 ANTI-ACIDS
35.2 ANTI-ACIDS
WHAT ARE ANTI-ACIDS?
We can take anti-acids to neutralize the excess acid in the
stomach. They usually contain chemicals such as:
magnesium hydroxide
aluminium hydroxide
magnesium carbonate
calcium carbonate
sodium hydrogencarbonate
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Figure 35.8 Anti-acid tablets.
35.2 ANTI-ACIDS
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A35.2
Dyspepsia (or indigestion): difficulty in digesting food
Heartburn: a burning feeling just below the heart, caused by
indigestion
Acid stomach: too much acid (gastric juice) produced in stomach,
causing pain
Flatulence: Uneasy feeling caused by gas generated in the
alimentary canal
35.2 ANTI-ACIDS
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MAGNESIUM HYDROXIDE/ ALUMINIUM HYDROXIDE
AS ACTIVE INGREDIENT
Magnesium hydroxide is slightly soluble in water, forming an
alkaline suspension. It can thus neutralize the hydrochloric acid in
stomach:
Mg(OH)2(s) + 2HCl(aq) MgCl2(aq) + 2H2O(l)
35.2 ANTI-ACIDS
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Figure 35.9 Magnesium hydroxide is the active ingredient of Philips’ Milk of Magnesia.
35.2 ANTI-ACIDS
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35.2 ANTI-ACIDS
Activity 2
Brief guidelines for the project are as follows:
A. To find the best buy according to greatest ‘neutralizing power’
per unit dollar
B. Comparison of the actions and side-effects on the active
ingredients
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35.2 ANTI-ACIDS
C. Other comparisons
• Size of packet
• Packaging
• Appearance of tablet (colour, size, shape etc.)
• Instructions to users on safe administration of drugs
• Availability in local market
D. Conclusion
Based on comparisons in Parts A, B and C, decide, as
objectively as possible, which brand of anti-acid tablets is of
the best buy. Give your reasoning.
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CARBONATE / HYDROGENCARBONATE AS ACTIVE
INGREDIENT
Carbonates or hydrogencarbonates neutralize acid in stomach
rapidly.
MgCO3(s) + 2HCl(aq) MgCl2(aq) + CO2(g) + H2O(l)
NaHCO3(s) + HCl(aq) NaCl(aq) + CO2(g) + H2O(l)
However, the effect is only short-lasting.
35.2 ANTI-ACIDS
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Figure 35.10
Magnesium carbonate and sodium hydrogencarbonate are the
active ingredients in this brand of anti-acid.
35.2 ANTI-ACIDS
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35.2 ANTI-ACIDS
‘Bismag’ antacid tablets react with dilute hydrochloric acid.
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35.3 ANALGESICS
35.3 ANALGESICS
WHAT ARE ANALGESICS?
Analgesics (or painkillers) are drugs to relieve pain.
The active ingredient in common analgesics is usually one
(or sometimes both) of the following compounds:
Aspirin
Paracetamol (also called acetaminophen)
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Figure 35.12 Some brands of analgesics.
35.3 ANALGESICS
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(a) (b) (c)
Figure 35.13
Common analgesics contain aspirin and/or paracetamol (acetaminophen) as the active
ingredient.
(a) Aspirin and Cortal contain aspirin.
(b) Panadol, Tylenol and Saridon contain paracetamol.
(c) Exedrin contains both aspirin and paracetamol.
35.3 ANALGESICS
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THE WONDER DRUG — ASPIRIN
Aspirin is the drug which is most widely used as a medicine. It
relieves pains (e.g. headache, toothache), and can reduce fever
(due to infectious diseases and colds) and inflammation.
Aspirin is the common name given to acetylsalicylic acid or
sodium acetylsalicylate.
35.3 ANALGESICS
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Figure 35.17 Beautiful willow trees. Aspirin was first made from willow bark.
35.3 ANALGESICS
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Figure 35.18 Formulae of the two forms of aspirin.
35.3 ANALGESICS
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Figure 35.19 One brand of soluble aspirin.
35.3 ANALGESICS
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35.4 PROBLEMS WITH DRUGS
35.4 PROBLEMS WITH DRUGS
SIDE EFFECTS OF DRUGS
Drugs may have undesirable side effects. Let us look at some
examples.
Aspirin irritates the stomach.
Some cough mixtures contain codeine. These may cause
drowsiness and possible addiction.
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Figure 35.21 This cough mixture contains a little codeine.
35.4 PROBLEMS WITH DRUGS
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A35.3
We should take aspirin after meal, together with a lot of water or
milk.
DRUG ABUSE
What is drug abuse?
Drug abuse includes the following:
Obtaining and using drugs (which should be prescribed)
without a doctor’s prescription.
Taking drugs for no medical reasons.
35.4 PROBLEMS WITH DRUGS
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Taking drugs exceeding the recommended dosage.
Taking a hypnotic or tranquilliser continually for a long period
of time, without a doctor’s guidance.
Sniffing solvents (e.g. glue, thinner, petrol).
Taking illegal drugs (e.g. cannabis, cocaine, heroin and LSD).
(This is particularly dangerous and will surely lead to early
death.)
35.4 PROBLEMS WITH DRUGS
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Figure 35.22
Some commonly abused drugs in
Hong Kong.
35.4 PROBLEMS WITH DRUGS
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DRUG DEPENDENCE
A person addicted to a drug is either physically or psychologically
dependent on the drug, or both.
Physical dependence
Psychological dependence
35.4 PROBLEMS WITH DRUGS
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The following guiding questions may be useful for this discussion:
(1) What are drugs?
(2) What are the main types of drugs and their uses?
(3) What are the side effects of drugs?
(4) What is drug abuse?
(5) What are the harmful effects of drug abuse?
(6) Is drug abuse serious in Hong Kong?
35.4 PROBLEMS WITH DRUGS
Activity 4
35
HARMS OF DRUG ADDICTION
Harm to drug addicts themselves
Harm to families of drug addicts
Harm to society
DRUG ABUSE IN HONG KONG
In recent years, there has been a rising trend in the number of
young people taking illegal drugs.
35.4 PROBLEMS WITH DRUGS
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Figure 35.23 Government posters against drug abuse.
35.4 PROBLEMS WITH DRUGS
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35.5 HAZARDS OF CIGARETTE SMOKING
35.5 HAZARDS OF CIGARETTE SMOKING
SMOKING CAN KILL
You may have seen many times the government health warning:
‘Smoking can kill’. This warning is no exaggeration at all.
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Figure 35.24 Hong Kong Government health warning: ‘Smoking can kill.’
35.5 HAZARDS OF CIGARETTE SMOKING
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Figure 35.25
A government anti-smoking
poster.
35.5 HAZARDS OF CIGARETTE SMOKING
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TRAPPING CIGARETTE SMOKE
We can trap smoke from a lit cigarette using a ‘cigarette smoking
machine’.
35.5 HAZARDS OF CIGARETTE SMOKING
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Figure 35.26 A ‘cigarette smoking machine’.
35.5 HAZARDS OF CIGARETTE SMOKING
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Experiment results show that high-tar cigarettes without filters
give out more tar than low-tar cigarettes with filters. Besides,
smokers inhale more harmful substances than passive smokers
do.
HARMFUL SUBSTANCES IN CIGARETTE SMOKE
Smoking produces more than 4000 chemicals. The main products
are:
Gases (or vapours)
Carbon dioxide
Carbon monoxide
Polycyclic aromatic hydrocarbons (PAHs)
35.5 HAZARDS OF CIGARETTE SMOKING
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Tar
Nicotine
Particulates
35.5 HAZARDS OF CIGARETTE SMOKING
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35.5 HAZARDS OF CIGARETTE SMOKING
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A35.4
Tar.
A35.5
6
35.5 HAZARDS OF CIGARETTE SMOKING
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Activity 6
Discussion could be based on the following points:
(1) Why do people smoke?
(2) Should smoking be banned completely? Why?
(3) Should smoking be restricted (e.g. in public areas)?
(4) If smoking is to be restricted, how should this be done?
(5) Should cigarette advertising be restricted? Why?
(6) Is restriction on cigarette advertising a violation of freedom of
speech?
35.5 HAZARDS OF CIGARETTE SMOKING
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(7) Should sponsorship for entertainments from cigarette
companies be forbidden?
(8) Do you think that the health hazard warnings on cigarette
smoking mentioned on cigarette packets and advertisements
are effective?
35.5 HAZARDS OF CIGARETTE SMOKING
48
SUMMARY
1. A drug is a substance which changes the state or function of
the human body.
2. Anti-acids are drugs that can relieve stomach trouble caused
by excess acid in the stomach. Milk of magnesia, with
magnesium hydroxide as the active ingredient, is a common
anti-acid.
3. Aspirin is a common painkiller, with acetylsalicylic acid as the
active ingredient. Panadol is another common painkiller, with
paracetamol as the active ingredient.
4. Drugs may have adverse side effects.
SUMMARY
49
SUMMARY
5. Drug abuse is very dangerous.
6. There are two types of drug dependence — physical
dependence and psychological dependence.
7. Smoking of cigarettes releases many harmful substances,
including:
Carbon monoxide
Polycyclic aromatic hydrocarbons
Tar
Nicotine
Particulates