6. Summary
Behind the symptoms of disease which lead to a diagnosis, there is a row of processes (metabolic pathways) involving many molecules. Sometimes, for various reasons, these processes or molecules stop working or do not work as they should. This leads to imbalances of the body’s homeostasis. The anaemia case (Example 2) shows that there are many different molecular processes behind a given symptom. This means that different pharmacological treatments are needed to cure the underlying disease or relieve the symptoms. Factors causing disease vary between individuals. This is due to different genetic dispositions and the body’s reserve capacity to maintain homeostasis. This means that external factors like microbes, chemical or psychological stressors may result in disease in some individuals but not in others.
It is the purpose of pharmacotherapy to restore homeostasis. This is done by identifying key molecules in the processes that are not working and by correcting their activity, either through inhibition, promotion or by supplementing components that are missing. However, to ensure that a medicine is effective, it is not enough to show that it acts on the target. It also needs to be shown to reduce the symptoms of the disease. This is done by measuring the effect on clinical endpoints in clinical trials with patients.