3.7 Discovery and Development of Drugs

• Origin of drugs

  Traditionally were extracted from plants and microorganisms.

  • Digitalis - treat heart conditions - foxgloves
  • Aspirin - lower fever - willow tree
  • Penicillin - cure bacteria caused infections - penicillium mould
• Recent Drug Manufacture

  Synthesised by chemists in the pharmaceutical industry

  Process may still begin with chemical extraction from plant
• Drug Testing

  
  

  • Toxicity - safety
  • Efficacy - effectiveness
  • Dosage - amount
• Drug Discovery

  • Drug is extracted from a plant or microbe/Drug is designed in a lab
  • The drug is synthesised by chemists in pharmaceutical industry
• Pre Clinical Trials

  Testing on human cells and tissues

  Testing on live animals

  • Toxicity, Efficacy, Dosage

  Arguments: animal cruelty or safest way to prevent human danger
• Clinical Trials

  Small group of healthy volunteers

  • ensure there are no harmful side effects, a very low does is given and gradually increased

  Positive results = People suffering from the illness

  • optimum does is found (most effective)

  Drug effectiveness: 2 Larger groups of patients
• Blind Trials


  50% given drug

  50% given placebo (substance like drug but does not do anything)

  Doctor is able to view the difference the drug makes and compares results

  Allows for placebo effect (patient expects treatment to work and feels better even though it is not doing anything)
• Double Blind Trials


  50% given drug

  50% given placebo

  Both the patient and doctor are unaware until all the results have been gathered.

  Avoids Bias from doctors who could be influenced by their knowledge.
• Results

  The results of the testing and trials are not published until they have been through peer review - prevents false claims