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Infectious diseases - medicines

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Developing medicines

To develop a new medicine it is important to understand how the human body works and how it is affected by a particular disease. A successful medicine treats hundreds of thousands or even millions of patients. It also makes money for the pharmaceutical company which in turn enables them to carry out research into more new medicines to treat more diseases. For any medicine to be successful it must be:

  • Effective
    it must prevent or cure the disease it is aimed at, or relieve the symptoms for the patient.
  • Safe
    it is very important that a medicine cures a problem without causing unacceptable side effects.
  • Stable
    it is important that the chemicals in the medicine can be used under normal conditions and be stored for some time.
  • Successfully absorbed and excreted by our bodies
    however good a medicine might be in theory, it is no use unless it can reach its target and then be removed from the body once it has done its work.

Research into a new medicine has to make sure that all these conditions are met. This is why it takes a very long time - up to 12 years - and a great deal of money - up to around £550 million - to bring a new medicine into the doctor's surgery.


Steps in developing a medicine

Different types of clinical trials

When new medical treatments are being tested there are a number of ways the trials can be run. These include:

  • Randomised trials
    most drug trials are randomised after phase II. This means that patients are selected at random to get the experimental treatment or a comparator. The comparator may be a harmless pill with no action (a placebo) or the best available current treatment.
  • Open label trials
    both the researcher and the patient know what drug they are being given. Sometimes this is inevitable if, for example, you are comparing a medical treatment with physiotherapy or exercise.
  • Blind trials
    the researcher knows if the patient is being given a trial drug or a placebo, but the patient does not - they are blind. The problem with this is that the researcher may give unconscious clues to the patient about whether they are getting the new treatment or not.
  • Double blind trial
    neither the researcher nor the patient know if the patient is being given the trial drug or not. Only a third person who is not involved in the research process has that information. This means that there is no chance of the researcher influencing the patient, consciously or not.

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