The use and abuse of drugs

1. The use and abuse of drugs 1.3 Drugs

2. Summary of Specification content • Testing of new drugs and clinical trials. • Thalidomide

3. Learning Outcomes • Define the term ‘drug’. • Give examples of medical drugs. • Explain why drugs need to be tested before they can be prescribed. • Describe the uses and problems associated with thalidomide. • Explain how the drug testing procedure for thalidomide was inappropriate. • Describe the main steps in testing a new drug. • Explain the terms placebo and double-blind trial.

4. Discuss: • what is a drug? • Names of medicines.

5. Medicines from plants • Drugs are chemicals • that affect the way cells work • That have an effect on the processes of the body • Medicinal drugs • Have a beneficial effect • Used for treating disease, injury and pain • Example: - Paracetemol • Effective painkiller • High doses can cause liver damage • In extreme cases it can be lethal

6. Recreational drugs • Some drugs are taken for pleasure • These include • Caffeine • Alcohol • Cannabis • Nicotine • Heroin

7. Natural medicines • Many of the chemicals used to make medicines occur naturally in plants • aspirin • white willow bark • quinine • to treat malaria • from Cinchona tree • morphine and codeine • analgesics • from opium poppies

8. Natural medicines • 75 – 80% of the world’s population use medicines originally derived from plants • Many of these plants are found in rainforests • The rosy periwinkle is the source of two chemicals that are used to treat cancer.

9. Obtaining drugs from plants • Many of the plants contain these chemicals to protect them from herbivores • Problem • they are harmful to other living organisms • could be potentially harmful to humans if used in drug preparations • So any potential drug has to be tested for: • efficacy • toxicity

10. Modern Drug Testing • Modern clinical trials are double blind trials, where some patients are given a placebo. • Placebo • compound presented in the same way • Double blind • neither doctors nor patients know who gets drug or placebo • avoids bias in ‘looking for results’

11. Modern Drug testing Stage 1: Laboratory Phase 1 Clinical trial Low doses tested on a group of healthy people Evaluate safety Identify side effects • Animals or tissues used in a lab to find out • Level of toxicity • Efficacy – does the drug work?

12. Modern Drug testing Phase 2 Clinical trial Phase 3 clinical trial Large groups of people Confirm effectiveness Monitor side effects • Larger group of people • See if it is effective • Further evaluate safety • Determine optimum dose

13. History of drug testing • Digitalis • is a natural toxin found in foxgloves • can be fatal in even quite small doses. • used for centuries in herbal remedies to treat some heart conditions. • William Withering rigorously tested digitalis and brought it into conventional medicine in 1775.

14. Testing a new drug

15. Testing a new drug • Compare the two flow charts by answering the following questions • What similarities are there? • What differences are there? • In what way is the current system of drug testing safer and more reliable? • What do we gain nowadays from testing the drug on healthy volunteers first? • Why is it important to randomly assign patients to the treatments and have a double blind trial?

16. What similarities are there? • In both cases a potentially useful medicinal substance was identified • First small and then larger groups of patients were treated with the drug

17. What differences are there? • The current method seeks single active ingredients • Animal trials are used before testing on humans to assess • efficacy • toxicity • Drug tried out on a group of healthy people first • confirms whether drug behaves in the body in the way predicted by the lab tests • effects of different doses monitored • Independent review of data carried out in current system

18. Further differences • Statistical analysis of data • to see if any difference is due to • chance • the drug • Once regarded as effective and safe drug has to be strictly licensed before it can be marketed

19. In what way is the current system of drug testing safer and more reliable? • Safer • Use of specific active ingredient should allow a more precise dose to be given • Any serious ill effects may be detected in the animal trials first • More reliable • Uses larger samples reduces effects of chance • Double blind testing avoids patient/researcher bias in observing, recording and interpreting effects • Statistical analysis of data improves accuracy of conclusions as to whether or not drug has an effect

20. What do we gain nowadays from testing the drug on healthy volunteers first? • Check no unexpected side effects • Observe behaviour of drug in a human e.g. is the compound absorbed, how is it distributed, is it metabolised and broken down too quickly, is it excreted before it has an effect etc.

21. Why is it important to randomly assign patients to the treatments and have a double blind trial? • Prevents • subconscious prediction or influence of the outcome by both patient and researcher • psychosomatic influences

22. In the news • Sometimes things do go wrong! • http://news.bbc.co.uk/1/hi/england/london/4811626.stm • Ethical issues here! • http://www.bbc.co.uk/science/hottopics/animalexperiments/ • http://www.beep.ac.uk/content/396.0.html • Even licensing can lead to controversy! • http://www.bbc.co.uk/stoke/content/articles/2005/09/26/herceptin_intro_2005_feature.shtml

23. Even licensing can lead to controversy! • http://www.bbc.co.uk/stoke/content/articles/2005/09/26/herceptin_intro_2005_feature.shtml

24. Use of animals in research • http://www.mrc.ac.uk/NewsViewsAndEvents/News/MRC003445 • http://news.bbc.co.uk/1/hi/sci/tech/5365206.stm

25. Thalidomide • Thalidomide • drug used in the 1960’s as a sleeping pill • Effective at relieving morning sickness in pregnant women, but had not been tested for this use • Reduced the development of blood capillaries in the foetus and babies were born with underdeveloped arms and legs • Banned as soon as these side effects were noticed • Currently used for • Treating leprosy • Treating cancer

26. Thalidomide Activities • Use pictures to relate uses and problems associated with thalidomide. • Research and produce a report on thalidomide – original use, use in pregnant women, current uses.

27. How Science Works - ICT • You have developed a drug that can make people more intelligent. Create a multimedia advertising campaign explaining what your drug can do and showing that it has been properly tested and is safe to use.

28. PPQ Jan 10 (H) Question 4 • (a) • testing for toxicity / see if it is safe / see if it is dangerous / to see if it works • ignore side effects unqualified 1 • (b)(i) • testing for side effects / testing for reactions (to drug) • ignore to see if it works • do not accept dosage

29. (b)(ii) any one from • dose too low to help patient • higher risk for patient • might conflict with patient’s treatment / patient on other drug • effect might be masked by patient’s symptoms / side effects clearer • ignore immune system

30. (c) • to find optimum dose • allow testing on larger sample or it makes results more reliable • allow to find out if drug is effective / find out if drug works on ill people • (not just if drug works)

31. (d)(i) • (tablet / drug / injection) that does not contain drug • allow control / fake / false • allow tablet / injection that does not affect body • do not accept drug that does not affect body • (d)(ii) • neither patients nor doctors

32. Drug trialling – Suggested Activities • Discuss: • Discuss drug safety and how drugs are tested today. • Activity: • Cards/cut-outs to sequence stages in drug testing and trialling and purpose of each stage.

33. Summary of Specification content • Statins lower the amount of cholesterol in the blood. • Recreational drugs

34. Learning Outcomes • Describe and evaluate the effect of statins in cardiovascular disease.

35. Cholesterol Revision • Cholesterol • is produced naturally in the liver • Some people have high cholesterol levels • Too much cholesterol • increases the build up of fatty deposits in artery walls • Increases risk of heart disease • Evidence that reducing cholesterol in the blood reduces the risk of heart disease and heart attacks

36. Statins • Statins • Reduce the production of cholesterol by the liver • Reduces blood cholesterol levels • Used to treat patients who are at risk because they have a high cholesterol and a history of heart disease in their family.

37. Task: Interpret data on statins

38. any two from: • balance between two important for good heart health • ignore blood pressure • high LDL causes heart disease / high Cholesterol • do not accept converse argument • high HDL reduces heart disease / cholesterol • do not accept converse argument

39. heart attacks greater amongst patients with low HDL levels • ignore statins cause heart disease • statins reduce heart attacks of patients or placebo is less effective • ignore comparative effects of the two statins • allow pravastatin is more effective supported by appropriate calculations

40. Revision – drug testing • T • toxicity • H • Healthy people for side effects • P • Patients for effectiveness • D • Patients for dose • Make your own mnemonic to remember the sequence of events in drugs testing.

41. Learning Outcomes • Name some recreational drugs. •  Describe some effects of caffeine on the body.

42. Recreational drugs • A drug is any chemical that alters how our body works • Drugs that affect the central nervous system control the movement of chemicals across the synapses. • Drugs have similar shapes to these chemicals and can mimic what they do. • Recreational drugs are taken for pleasure

43. Recreational drugs Legal Illegal Cannabis Cocaine Heroin Ecstasy All of these may have adverse effects on the heart and circulatory system. • Alcohol • Caffeine • Nicotine

44. Drug Dependence Chemical Dependence Psychological dependence the person feels a need for the drug. They feel unable to cope without the drug. For example: some smokers need to chew sweets after they give up because they miss having a cigarette in their mouths. • the body adapts to the presence of the drug. • When the chemical is removed the body is no longer able to function normally. • The body then goes into withdrawal symptoms such as hallucinations, fevers, nausea (feeling sick) and shakes. • These are real, physical signs.

45. Caffeine • A stimulant is a drug that increases the activity of the nervous system. • It can raise the alertness, emotions or mood. • Caffeine is a mild stimulant found in tea and coffee. • Prolonged overuse may lead to problems with the heart, stomach and pancreas.

46. Discuss: Brainstorm on recreational drugs, sort into legal and illegal and discuss why people use them. • How Science Works: Investigate the effect of caffeine on heart rate or reaction time

47. Summary of Specification content • Recreational drugs • Impact of legal drugs on health is greater than illegal drugs as more people use them.

48. Learning Outcomes • Evaluate the impact of smoking on health. • Evaluate why some people use illegal drugs for recreation. • Evaluate claims made about the effect of prescribed and non-prescribed drugs on health.

49. Smoking Benson And Hedges Gold 20 Pack £7.25 Lambert And Butler King Size 20 Pack £6.89 • Decide how many cigarettes you are going to smoke in one day • Calculate how much you will spend on cigarettes in a week • Calculate how much you will spend on cigarettes in a year • If you started smoking at 16 and continued to smoke until you were 65, how much money will you have spent on cigarettes?

50. Smoking and Health • To understand the effects of smoking you need to look at the three components of cigarette smoke • Nicotine • Carbon monoxide • Tar