Testing medicines

• New medicines

  Developed all the time, have to be extensively tested
• Sources of new medicines

  • Extracted from plants
  • Extracted from microorganisms
  • Synthesized by chemists
• Drug testing process

  1. Preclinical testing on cells, tissues, or live animals

  2. Clinical testing on healthy volunteers to check safety

  3. Clinical testing to find optimal dose
• Placebo

  Tablet or injection with no active drug
• Double-blind trial

  Test group receives active drug, control group receives dummy drug, neither patients nor doctors know who is receiving what
• Double-blind trials are to stop bias in case doctors pay closer attention to people receiving the active drug
• Digitalis is a heart drug


  Extracted from foxglove
• Aspirin is a painkiller 


  Extracted from willow trees
• Penicillin is an antibiotic 


  Extracted from penicillium mould
• Drugs tested for

  • Toxicity (is it safe)
  • Efficacy (does it treat the disease)
  • Dosage (optimum amount)
  • Side effects (fewest side-effect)