Question: How do you find out if a medicine works or not?

Katherine Jones answered on 21 Jun 2011:

This is a very long process… it takes about 5-10 years from the first time we make a medicine. We have loads and loads of tests on the medicine, but here are the main ones:

First of all, we take a certain enzyme that we are trying to affect, and we look at the effect of the medicine on the enzyme.

If this is good, we test the medicine on human blood. This blood comes from a donation unit where members of staff can give the blood.

When we have done these tests, we look at how the medicine affects enzymes in the liver. This gives us information about how long the medicine might stay in the body for.

If all of these are good (probably less than 1% of the things we make), we give the medicine to a rat or mouse. We then take blood and urine samples from the animal. The information we get from this lets us understand how much medicine we will need to give to people.

After all of this, we decide which medicine we are going to give to people, to see if it works. When we have decided, we do some more tests on rats or mice. This involves giving the medicine to the animal and seeing if there are any nasty side effects. We have to do this before we give it to people, as the side effects can sometimes be really bad, such as giving them cancer or affecting their heart.

Once all this is done we give the medicine to healthy people first, who volunteer. This is because we want to get as much information as possible before we give it to sick people, who are a lot more vulnerable.

In the end, if everything is good, we give the medicine to patients. A small number to start with, and then we increase it if we see positive results. If all goes well, we are then given a license to make the drug!

Phew… it is a very long process. It takes about 10 years and costs about $1 billion to get a medicine that works to patients!!