Drug Development & Testing Flashcards
What is a poison?
A relative term relating to the dose necessary to cause harm to an organism
When does a poison become classified as a medicine?
If it can kill pathogenic microbes or maligent cancer cells at a dose level which leaves humans alive
What are the characteristics of foxglove leaves?
They are poisonous when eaten by humans and other animals. They have a strong bitter taste
What are the symptoms of foxglove poisoning?
Dizziness, vomiting, hallucinations and heart failure caused by an irregular heartbeat
What is dropsy now called?
Oedema
What is dropsy?
It happens when fluid accumulates in the body tissues. This process is painful and can cause a slow death. It is usually caused by heart or kidney problems
Why was William Withering interested in foxgloves?
He had heard that it was a cure for dropsy
How many patients did WW study to discover the side effects of digitalis? What did he find?
163 patients. He discovered the side effects of digitalis were nauseam vomiting, diarrhoea and green/yellow vision
What did WW find was a sign of recovery?
The production of a large quantity of urine
How did he discover the correct dose for his patients?
He slowly increased the dose until the patients showed the side effects, he then reduced it very slightly. This was the most effective dose
How did WW communicate his findings to other scientists?
He wrote a book about the medicinal properties of the foxglove
What three criteria does a new drug have to satisfy?
1) It has to be safe
2) It has to be effective
3) It has to be capable of making a profit
To find a new drug potential substances are?
Analysed and the active ingredient is identified and copied so it can be synthetically manufactured
Why are slight variations (analogues) made of the chemical structure?
Just in case they might have a better effect
How are most new drugs discovered nowadays?
Through computer modelling of their chemical structures
Who are pre-clinical trials carried out on?
Animals and isolated cells/tissue cultures
What is the purpose of pre-clinical trials?
To assess safety and determine whether the compound is effective against the target disease
How long do pre-clinical trials usually take?
Several years
Who are phase 1 clinical trials carried out on?
A small group of volunteers, usually healthy
What is the purpose of phase 1 clinical trials?
To confirm whether or not the drug is being absorbed, distributed, metabolised and excreted by the body in the way predicted by lab tests
Who are phase 2 clinical trials carried out on?
A small group of around 100-300 of volunteer patients with the disease
What is the purpose of phase 2 clinical trials?
To look at the drugs effectiveness
Who are phase 3 clinical trials carried out on?
A large group of around 1000-3000 patients randomly divided into two groups
What is the purpose of phase 3 clinical trials?
To see if the results will show a statistically significant improvement in patients receiving the drug compared to the placebo
What is involved in the testing process for phase 3 clinical trials?
One group is given the compound being investigated, the second is given a placebo. It is a double blind trial
Who are phase 4 clinical trials carried out on?
Everyone who buys the medicine
What is the purpose of phase 4 tests
To collect data on the effectiveness and safety of the new drug
