Developing Drugs

• There are 3 main stages in developing drugs:

  • preclinical testing on human cells and tissues
  • preclinical testing on live animals
  • clinical trials on human volunteers
• Preclinical testing 1:

  • drugs are tested on human cells and tissues in a lab
• You can't use human cells and tissues to test drugs that affect whole or multiple body systems e.g. a drug for blood pressure must be tested on a whole animal because it has an intact circulatory system
• Preclinical testing 2:

  • testing the drug on live animals
  • to test for efficacy, find out the drug's toxicity, and find the best dosage
• Efficacy

  whether the drug works and produces the right effect
• Toxicity

  how harmful the drug is
• Dosage

  the concentration of the drug that should be given, and how often it should be given
• Some people think it is cruel to test drugs on animals, but others believe it is the safest way to make sure a drug isn't dangerous before it's given to humans
• Clinical trialling 1

  the drug is first tested on healthy volunteers to make sure it doesn't have any harmful side effects when the body is working normally. A very low dose of the drug is given, then is gradually increased
• Clinical trialling 2

  if the results on healthy volunteers are good, the drugs are tested on people suffering from the illness, and the optimum dose is found
• Optimum dose

  the dose of a drug that is the most effective and has the least side effects
• Clinical trialling 3

  patients are randomly put into 2 groups - one is given the drug, the other is given a placebo. This is so the doctor can see the actual difference that the drug makes, and allows for the placebo effect
• Clinical trials are blind and often double-blind, so that the doctors monitoring and the patients analysing the results aren't subconsciously influenced by their knowledge
• Blind trial

  the patient doesn't know whether they're getting the actual drug or the placebo
• Double-blind trial


  neither the patient nor the doctor knows which patients have the drug and which have the placebo until all the results have been gathered.
• Clinical trialling 4

  the results of drug testing and drug trials aren't published until they've been through peer review, to help prevent false claims
• Peer review

  when other scientists check that the work is valid and has been carried out rigorously
• Placebo

  a substance that's like the drug being tested but doesn't actually do anything
• Placebo effect

  when the patient expects the treatment to work so they feel better even though it isn't doing anything