Fighting Disease - Drugs

• Painkillers

  drugs that relieve pain and reduce symptoms but don't actually kill pathogens
• Antibiotics


  drugs that kill or prevent the growth of the bacteria causing the problem without killing your body cells
• Antibiotics don't destroy viruses, because they reproduce using your own body cells, so it is difficult to develop drugs that destroy the virus without killing the body's cells
• The use of antibiotics has greatly reduced the number of deaths from communicable diseases caused by bacteria
• Bacteria can mutate, which means they can become resistant to an antibiotic
• If you have an infection, some of the bacteria might be resistant to antibiotics, which means that only the non-resistant strains of bacteria will be killed by treatment
• The individual resistant bacteria will survive and reproduce and the population of the resistant strain will increase (natural selection)
• The resistant strain of bacteria could cause a serious infection that can't be treated by antibiotics, e.g. MRSA causes serious wound infections and is resistant to the powerful antibiotic meticillin
• To slow down the rate of development of the resistant strains of bacteria, doctors must avoid over-prescribing antibiotics
• It is important that you finish the whole course of antibiotics and don't stop once you feel better to slow down the rate of development of resistant strains of bacteria
• Plants produce a variety of chemicals to defend themselves against pests and pathogens
• Some plant chemicals can be used as drugs to treat human diseases or relieve symptoms
• Aspirin

  a painkiller used to lower fever that was developed from a chemical found in willow
• Digitalis

  a drug used to treat heart conditions that was developed from a chemical found in foxgloves
• Development of penicillin:

  • Alexander Fleming noticed that one of his petri dishes containing bacteria had mould on it
  • he saw that the area around the mould was free of the bacteria
  • he found that the mould on the petri dish was producing a substance that killed the bacteria (penicillin)