What will happen to me during a clinical trial?


If you agree to join a trial, you may have more medical tests before you are given any treatment. This will allow the investigators to know where you started, so they can tell at the end of the trial whether there has been any improvement. These are called baseline measures. During the trial you may have more tests to see whether the treatment is working. These are known as outcome measures. This may involve more visits to the clinic than normal, or more tests than normal - for example, extra blood might be taken when you give a blood sample. Sometimes the tests are carried out as part of your routine care. You may have to make some changes to your everyday life. This may include avoiding certain foods or over-the-counter medications like anti-histamines. You may also be asked to keep a diary. This could contain notes about how you are feeling after your treatment, whether you get a particular side effect, and how long it lasts. As well as measuring the physical effects of a treatment, many trials now try to assess the impact on people's quality of life. For example, a 'quality of life' study might ask you about:

  • Your mood and general sense of well-being
  • Whether you feel more tired than usual
  • Whether you are managing to lead the life you would lead normally – going to work, looking after your family, or whatever you would normally do. You and your doctor might decide that you should stop taking part in a trial if your condition is getting worse and the treatment is not helping you. You can choose to leave at any point in a trial without giving a reason and without it affecting the level of care you receive. Do not be concerned if you want to leave a trial because you are experiencing side-effects. The information will still be useful to others. The investigators may want to continue to follow your progress after the trial, even if you left early. This helps them to interpret the results of the trial accurately.