Certain drugs can be extracted from natural sources and have been known about for a long time. For example, willow bark was used by the ancient Greeks to help cure fevers and pains. It was later discovered that the active ingredient was salicylic acid. This was modified by chemists into the substance we call aspirin, which is less irritating to the stomach than salicylic acid. Another example is the heart drug digitalis, which is extracted from foxgloves.
Plants are still important today, but most plant drugs are now created in a laboratory by scientists at pharmaceutical companies. These companies now have synthetic versions of the plant extracts and use these as the starting point to develop new drugs.
New medical drugs have to be tested to ensure that they work and are safe, before they can be prescribed. Drugs are tested for:
This is important as some drugs are toxic and have other side effects that might be harmful to people
This is also known as efficacy and checks how well the drug cures the disease, or improves symptoms.
This varies and has to closely controlled, as too high a concentration might be toxic.
There are three main stages of testing:
During clinical trials it needs to be determined if the drug is more effective than current treatments. This may involve asking the patient if they feel better or not. To avoid bias a number of strategies are applied:
Some people consider drug trials to be dangerous, so how safe are they? Everything comes with a level of risk.
Placebos are also used to ensure that the drug is having an effect and that any changes are not due the experimental trial process.