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What we have discussed so far is mainly related to external evidence and not the doctor’s own clinical experience or the patient preferences. Let’s consider an example.

Lisa has serious pain following surgery. The doctor knows that according to external clinical evidence, tablets containing morphine would be the best choice. However, a common side effect of the anaesthesia given to Lisa during surgery is vomiting. This means that if Lisa is given a tablet and starts vomiting, the tablet will be brought up and she will get no pain relieving effect. The doctor and Lisa know from experience, that Lisa is likely to start vomiting within 30 minutes after anaesthesia has ended. Therefore, the doctor decides to give Lisa an injection containing morphine instead.

In the example, the doctor decides, based on personal clinical experience and patient preferences, to use a morphine injection instead of tablets containing morphine, which have the best external clinical evidence. The doctor uses the same medical compound (i.e. morphine), as suggested in the external clinical evidence, but chooses to use a different formulation (i.e. injection instead of tablet). The doctor’s choice is perfectly in line with the principles of evidence-based medicine. His decision includes conscientious, explicit and judicious use of the best evidence at the current time point when deciding how to provide the best possible medical treatment for a given patient.