Question: how do you differentiate between drugs that have positive and negative effects on certain illnesses?

Katie Fala answered on 20 Nov 2019:

That’s a great question, I suppose that generally speaking a disease will have been characterised in high detail and we will already know the organs and biochemical pathways that are affected. Following from that, scientists figure out targets e.g. a faulty protein to which the drugs may be designed, considering the underlying biology/chemistry – so it’s not a shot in the dark but rather an educated guess. A prospective drug can then be modelled to predict the overall effects, positive and negative, using lab-based models like lab-grown cells or animals but also increasingly using software that mimics the different organs and biochemical pathways in the body. If it is promising enough to be brought through to clinical trial, more and more detail will be gathered on how effective it is at what dose, as well as any side effects, and whether or not they outweigh the beneficial effects. Most drugs will have side effects in addition to the therapeutic effect so it is often a case for the doctor to weigh up the risks/benefits. To give an example, thalidomide is perhaps best-known for being released to market without robust testing and causing thousands of miscarriages and instances of babies being born with severe birth defects. These extremely negative effects were not know of at the time of release, however are only relevant to pregnant people. It is still used today to treat leprosy and certain cancers.