development of drug testing

• pre clinical trials

  • modelling potential effects using computers
  • tested on human tissues in lab , then animals
• clinical trials

  phase 1= range of doses tested on small group of healthy people to check for safe dosage

  phase 2=small group of patients with the condition to see if drug has an effect/is effective

  phase 3=large group of patients tested on for effectiveness and side effects are recorded, this phase involves double bind trial(placebo)
• Explain why healthy volunteers are given different doses of drug or a placebo 

  -       Check for side effects 

  -       Different doses to determine a safe dose 

  -       Placebo to make sure that any side effects describe were due to the drug
• Describe how clinical trials of a vaccine would be conducted (3) 

  -       Small group of healthy volunteers are given the vaccine to test for side effects 

  -       Healthy volunteers tested for presence of antibodies to the virus following vaccination 

  -       A group of people at risk of contracting the disease is given the vaccine 

  -       The number of people who develop the viral disease following vaccination are monitored
• Explain the role that a placebo and a double bind trial have in producing valid conclusions

  Placebo 

  -       Provides a control group for comparison 

  -       Therefore, ensuring the active ingredient is causing the effect 

  Double bind trial 

  -       Because neither doctors nor patients know who has been given the actual drug 

  -       Therefore, ensures that bias is removed from the trial

   
• Describe how the safe dose of a cancer drug could be determined 

  -       Test the drug on healthy individuals/animals/cell cultures 

  -       Then test on group of individuals with cancer 

  -       Gradually increasing the dose to determine dose that does not cause side effects 
• Explain 4 reasons why a contemporary drug testing protocol is an improvement on the trial used by William withering (4)

  -       Safer due to pretesting on cells/animals before and pure drug used rather than extract 

  -       More valid- placebo used as a comparison, involves double blind trials 

  -       More reliable- more people are tested, results analysed statistically
• Describe how double-blind trial can be carried out (4) 

  -       With a large group of people with illness 

  -       Of similar age/gender/lifestyle 

  -       Divided into 2 groups, one given the new drug and other given alternative treatment or placebo (inactive substance)

  -       Neither the patients nor doctor know who is in which group

   
• Compare and contrast this drug testing protocol with that used by William withering when he tested digitalis soup 

  -       Both trials used different doses to determine safe dosage 

  -       William withering did not use healthy volunteers and this drug trial did 

  -       William withering did not use a placebo while this trial did
• digitalis soup

  • william withering
  • treatment for swelling caused by heart failure
  • used digitalis- extract from fox glove as different dosages/conc.
  • without poisoning patient