Question: Hello Paul! How do you help ensure that new medicines are safe and effective before they are given to people?

Paul Terrill answered on 24 Mar 2025:

Before any new medicines are tested on humans we do rely on animal experiments, but even before that a lot of work is done in labs using various tests. To start with very low doses are used and only if things lok ok then is the dose increased. Typically first experiments on humans are done on healthy volunteers, again starting with very low doses. Once there is confidence in the safety of a new medicine then it is tested in patients using randomised designs – some people are randomised to recieve the new medicine and others to recieve either a placebo (something that biologically does nothing) or an exisiting medicine. Lots of measurements assessing both safety and effectiveness are taken. The results are compared using statistical methods to look for strong evidence that the medicine is safe and effective. Several of these clinical trials are performed, and if successful then it is concluded that the medicine is effective and safe and can be given to people by doctors.

It takes many years an a lot of time and money to develop and test a medicine and a lot of possible new medicines do not work as hoped and do not get given to people.