Biology Revision

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  • Created by: Katie
  • Created on: 19-02-13 17:24

The use and abuse of drugs

A drug is something that affects our body chemistry - it can have a positive or a negative affect.

Developing New Medicines

A good medicine is...

Effective: it must prevent or cure a disease, or at least make you feel better.

Safe: not toxic or have unacceptable side-effects.

Stable: can be used under normal conditions and can be stored for some time.

There is up to £350 million spent on developing/testing drugs. The placebo effect is when a substance is given that has no effect on the patient. Refer to page 27 of revision guide.


  • Was developed in 1950's - sleeping pill.
  • Found to stop morning sickness during pregnancy.
  • One flaw was that it wasn't tested on pregnant animals or women - therefore didn't know if it was actually beneifical or successful on use of women.

How affective are new medicines?


Developing new medicines

  • When new drug is discovered - two main things it should/shouldn't do.
  • It should fulfil it's criteria or needs.
  • It shouldn't have harmful side effects.
  • Other things to consider are
  • Is it stable so that it can be easily stored?
  • It is easily passed from the body once its done it's job?
  • Flow chart with sequence of events to be carried out when testing new drug.
  • Scientists have an idea for a new drug for a specific drug.
  • They use computers to design and screen the new drug.
  • The new drug is synthesised (made) in the lab.
  • The drug is tested in vitro. This means - a process/reactions that take place outside a living organism.
  • If it passes these tests it is then tested on live animals - see if it will work on whole living organisms. This provides information about the dosage needed and any possible side effects.
  • It can then be tested on healthy people to make its safe to use.
  • A large number of people with illness drug is designed for will be tested on.
  • A large number of people will then be tested.
  • If it passes all these tests it will then be licensed and pharmacies/doctors will be able to prescribe it.
  • Trials will still continue to monitor the drug even after its been licensed.

About drugs:

  • Drugs change the CHEMICAL processes in your body - can become addicted.
  • Solvent, alcohol, tobacco and other drugs may HARM your body.
  • Smoking cannabis may cause MENTAL problems and solvents can damage the LIVER, LUNGS AND BRAIN.
  • Hard drugs (cocaine & herion) are very ADDICTIVE and can cause serious health problems.
  • Examples of withdrawal symptoms: shaking, acting out of characters, depression, cravings, violent behaviour.
  • Example of


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