B1- Biology- B3.1 - B3.6 (Medicine and Drugs)

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  • Created on: 29-05-15 14:22

Developing New Medicine

Key Points

  • When we develop and test new drugs they need to be extensively tested before we can use them
  • Drugs are tested to see if they work well. We also make sure they're not too toxic and have no unacceptable side effects
  • Thalidomide was developed as a sleeping pill and was found to prevent morning sickness in early pregnancy. It had not been fully tested and it caused birth defects. Now it is used to treat some cancers and Leprosy.


Examiners Tip!

Make sure you know that a medicinal drug is tested to see its

  • Effeciency
  • Toxicity
  • Most appropriate dose
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Testing Medicinal Drugs

There are 3 main stages to testing medicinal drugs

Stage 1

  • Tested on human cells and tissues in the lab
  • However you cant test it on cells if the drug is made to effect the whole/ multiple body systems- Testing a drug for blood pressure must be done on a whole animal because it has an intact circulatory system

Stage 2

  • Test on live animals to see if the drug works (produces the wanted effect), to test its toxicity (how harmful) and to find the best dose (which dose is most effective)
  • The law in Britain states it must be tested on two different live mammals. Some people think its cruel however its the safest way to test its danger
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Testing Medicinal Drugs (Continued)

Stage 3

  • If the drug pases the test on animals, it tested on human volunteers in a clincial trial
  • First, tested on healthy volunteers to make sure there are no harmful side effects on a healthy person. A very low dose is given and then gradually increased
  • If the results on the healthy volunteers is good, the drug can be tested on people suffering from the illness. The optimum doese is found- the most effective doese with the fewest side effects
  • To test how well the drug workd, patients are put into 2 groups. One is the new drug, and one is the placebo. This way the doctor can see if the drug makes a difference- it allows for the placebo effect.
  • Clinical trials are blind- The patient in the study doesnt know whether they're getting the drug/ placebo. They're often double blind- Patient and doctor does not know what they are getting until all the results are gathered. This is so the doctors monitoring the patients and analysing the results aren't subconsciously influenced by their knowledge.
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How Effective Are Medicines?

Key Points

  • Statins lower the amount of cholesterol in the blood and can reduce the risk of cardiovascular disease by up to 40%
  • The effectiveness of both prescribed and unprescribed drugs can only be measured in proper double-blind trials
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Key Points

  • Drugs can change the chemical process in your body cand you may become addicted to them. If the drug isnt taken, an addict can suffer from withdrawl symptoms. These are sometimes very unpleasant
  • Addiction is when you become physically or mentally dependant on a drug
  • Smokinf cannabis may cause mental health problems
  • Hard drugs such as cocaine and heroin, are very addictive and can cause serious health problems

Drugs can be Medicinal, Recreational or Performance-Enhancing

  • Medicinal drugs are medically useful like antibiotics.
  • Recreational drugs are for fun. These can be legal or illegal
  • Performance enhancing drugs can improve a persons performance in sport
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Drugs (Continued)

Performance enhancing drugs have health and ethical impacts

  • Some athletes take these to make them better at sports.
  •  There are several types including, anabolic steroids (increase muscle size) and stimulants (that increase heart rate) 
  • These drugs can have negative health effects- can cause high blood pressure
  • Some of these drugs are banned by the law, some are prescription-only but all are banned by sporting bodies
  • There are also ethical problems with taking performance enhancing drugs

Against Drugs

  • Unfair people gain an advantage by drugs and not training
  • Athletes may not be fully imformed of the serious health risks

For Drugs

  • Right to make their own decision
  • Drug-free sport isnt fair anyway. People have different training facilities, coaches, equiptment ect
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Legal and Illegal Drugs

Key Points

  • Many recreational drugs affect the nervous system particularly the brain. Some are more harmful than others
  • Some recreational drugs are legal and some illegal
  • The overall impacts of legal drugs on health is much greater than illegal drugs because more people use the,
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