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The use and misuse of drugsPresentation Transcript
The Use and Misuse of Drugs Block 8, part i
Medical DrugsLearning objectives:• Know that disease may be treated with medicines that contain useful drugs (e.g. penicillin is an antibiotic, aspirin is anti-inflammatory)• Know that some medicines, including painkillers, help to relieve the symptoms of disease, but do not provide a cure (for example, aspirin, paracetamol, treatments for high blood pressure, antidepressants and sleeping tablets)
Drug use and abuseHow often do you see drugs being used?
What are drugs?A drug is any chemical substance that affects thephysiological state of the body, such as how the centralnervous system (CNS) works.Drugs can be categorized according to whether they arelegal or illegal, or by the type of effect they have on the body.E.g. analgesics relieve pain (pain killers)What is the difference between a medical and recreationaldrug?Write a definition for each in your note books.
Why people take drugs...Medicinal drugs (e.g.painkillers, antibiotics) areused to treat (cure) diseasesor prevent symptoms. Theyare obtained either with aprescription or over-the-counter at a pharmacy.Recreational drugs (e.g.alcohol, nicotine, ecstasy)are used for leisurepurposes, because theycause changes in mood,behaviour or perception.
Which type of drug?
Why do drugs need to be controlled?Illegal drugs have no quality control. It is impossible to knowhow strong the dose is, or which substances the drugs havebeen mixed (‘cut’) with. Some drugs may only be 1% pure.Medicinal drugs can be equally dangerous.Doctors are careful to prescribe the rightamount of medicine to preventpatients from overdosing.How are prescription andover-the-counter drugs developed?
How are new drugs developed?
Drug trialsFew drugs successfully pass each stage of development.For every new drug launched, thousands are abandoned. To minimize bias in drug trials, patients and doctors are not told who receives the study drug and who takes a placebo: an inactive substance that looks like the drug. This is called a double-blind placebo-controlled trial. How does this help?The drug must be tested in thousands of patients to see howeffective and safe it is. Why are so many patients needed?
What was thalidomide?Thalidomide was a drug used in the 1950sand 1960s as a sleeping pill. However,pregnant women who were given the drugto prevent morning sickness gave birthto babies with limb deformities.How did this happen?The drug manufacturers had tested thalidomide in animals,but the tests on pregnant animals had not been completed.Since then, drugs have had to be tested according to verystrict guidelines.Thalidomide is now being tested for the treatment ofdiseases such as leprosy and some cancers.
Is Caffeine a Stimulant?Aim: to perform a double-blind, placebo-controlled trial on the drug caffeine.My results: Before Taking After taking ‘Drug’ ‘Drug’ Pulse rate: (____) Mean reaction time: (___)Conclusion:After taking the caffeine/placebo* drug my pulse __________and my reaction time__________.*Delete as appropriate
Converting Distance in Reaction Time Distance on Ruler (cm) Reaction Time (s) 5 0.10 10 0.14 15 0.17 20 0.20 25.5 0.23 30.5 0.25
Recreational DrugsRemember drugs can be categorised by their affect on the body: stimulants – e.g. caffeine, cocaine, amphetamines depressants – e.g. alcohol, barbiturates, heroin hallucinogens – e.g. LSD, cannabis
What do stimulants do?Stimulants speed up the activity of the nervous system byincreasing the release of neurotransmitters at certainsynapses in the brain. This causes: increased alertness improved memory and endurance raised heart rate and blood pressure reduced appetite.Common stimulants includecaffeine, nicotine, cocaineand ecstasy.
What do depressants do?Depressants slow down the activity of the nervous system byreducing the release of neurotransmitters at certain synapsesin the brain.This results in sleepiness andreduced anxiety, but high dosescan lead to addiction.Common depressantsinclude alcohol, solventsand barbiturates.Some depressants, such asheroin, also reduce pain.
Drug ResearchYou will be asked to give a 5 minute talk next lesson on one particular recreational drug. You must work as a team and include the following information in your presentation:• Type of Drug – Legal/Illegal and Stimulant/ Depressant/ Hallucinogen.• Effects on the body – detailed description of what happens when you take this drug (physically and psychologically)• Addiction – how addictive the drug is and steps to overcome addiction• Withdrawal symptoms – what can happen when an addict stops taking the drug• Other interesting facts – e.g. Does it have any positive effects or medicinal uses?
What is tobacco?Tobacco is made from the leaves of thetobacco plant, which contain smallamounts of nicotine. Cigarettes aremade from finely cut and dried tobaccoleaves.When tobacco smoke is inhaled, thenicotine quickly enters thebloodstream and has a stimulatingeffect on the nervous system.At high concentrations nicotine ispoisonous and is used as insecticide!
The dangers of smoking
Spot the differenceWhich set of lungs would you prefer to have?
NicotineNicotine is addictive because it increases levels of theneurotransmitter dopamine in the brain. This producesfeelings of enjoyment and motivation.Many smokers find it difficult to quit smokingbecause of the symptoms of nicotinewithdrawal, which include: headaches anxiety and sleeplessness weight gain.What type of products areavailable to help smokers quit?
The effect of smoking on oxygen supply Red blood cells are normally saturated with oxygen when they leave the lungs. alveolus in the lung Carbon monoxide in cigarette smoke prevents red cells from picking up oxygen.capillary oxygen carbon monoxide carbon dioxide red blood cells
Effect of cigarette smoke chemicals
What is addiction?A person is said to be addicted to, or dependent on, a drugwhen they feel unable to stop taking it. There are two types ofaddiction: physiological addiction – the person is compelled to take the drug to avoid or reduce unpleasant or dangerous withdrawal symptoms. psychological addiction – the person is compelled to take the drug to experience the effect it produces, rather than to treat withdrawal symptoms.
What is alcohol?Alcohol is a family of relatedsubstances, but most commonly refersto ethanol – the active ingredient inalcoholic drinks.Alcohol is quickly absorbed into thebloodstream, where it starts to have aneffect on the CNS.The effects of alcohol vary from person to person and withfactors such as: rate of consumption level of food/water intake age and gender body weight/body fat.
The short-term effects of alcoholSmall amounts of alcohol cause a person to feel relaxed andless inhibited. It can therefore appear to stimulate people.However, further consumption has a depressant effect,making reactions uncoordinated and impairing speech.Alcohol is a diuretic, whichmeans it causes more urineto be produced than normal.This can lead todehydration, whichcontributes to a hangover!Alcohol also makes blood vessels dilate, leading to heat loss.
Effects of alcohol by dose
Physiological effects of alcohol
How much is it safe to drink?The UK Department of Health advises that men shoulddrink no more than 4 units of alcohol per day, and womenno more than 3 units.How much is 1 unit of alcohol? Drink Units of alcohol 1 pint of strong lager 3 1 pint of bitter 2 1 pint of cider 2 175 mls of wine 2 1 alcopop 1.5 35 mls of spirit 1
The long-term effects of alcoholLike all drugs, alcohol is broken down, or metabolized, by theliver.Over time, heavy drinkingdamages liver cells, causingthem to produce fibrous scartissue which blocks liverfunction. This is a diseasecalled cirrhosis.Heavy drinkers are also at increased risk of cancer anddamage to the brain, kidney and immune system.
AntibioticsLearning Objectives:• Know what antibiotic are and what diseases they can be used t treat• Describe how antibiotics work• Explain why antibiotics cannot be used to treat viral illnesses
What are antibiotics?Antibiotics are a group of drugsused to treat bacterial infections.They are effective against bacterialcells but they generally leaveanimal (human body) cellsunharmed. There are two different types of antibiotics: bactericidal – kill bacterial cells bacteriostatic – slow the growth or reproduction of bacteria.
Antibiotic resistanceIn the presence of an antibiotic, somebacteria can mutate leading to types(strains) that can become resistance tothat antibiotic.They are able to survive andreproduce, giving rise to a populationof antibiotic-resistant bacteria.In some cases this resistanceis evolving faster than thedevelopment of new antibiotics.M. tuberculosis has evolved resistance to streptomysin andother antibiotics. Multi-drug resistant TB is still relativelyrare, but there is growing concern about its spread.
Antibiotic resistance: MRSA The bacteria Staphylococcus aureus has become resistant to most antibiotics, including methicillin. This methicillin- resistant S. aureus (MRSA), which is becoming common in hospitals, can cause a life-threatening infection.Due to the emergence of antibiotic resistance, severalmethods of prevention and control have been adopted: antibiotics should only be prescribed when needed patients should finish the complete course of antibiotics introduction of infection control in hospitals.
True or False?1. Antibiotics are used to kill viruses2. Antibiotics are medicines3. Antibiotics are prescribed by doctors4. Antibiotics are used to kill bacteria5. You must finish all of the antibiotics to reduce the risk of bacteria becoming resistant6. Different types of antibiotic will kill different types of bacteria7. Fungi never become resistant to antibiotics8. MRSA are bacteria which can be killed by many antibiotics.9. Some antibiotics weaken the cell walls of bacteria so they die
Chickens raised in barns are given If you are in hospital after an operation antibiotics you should be given antibiotics It is really important that you alwaysIf you have a cold you should go to the finish a course of antibiotics even if you doctor for some antibiotics are feeling better In some countries, antibiotics can be In this country you can only get bought over the counter antibiotics from your doctor Milking cows may have tubes of Pigs are sometimes given antibiotics to antibiotics placed under their udders make their muscles grow faster Some chopping boards have Animals should be given antibioticsantibacterial substances built into them after operations