Biology - Use of Drugs (AQA)
New drugs have to go through rigorous testing procedures before they are allowed to be used on the public.

Biology - Use of Drugs (AQA)

In GCSE Science students will look at drugs, both recreational and medical. This is the first of two quizzes on the subject and it concentrates on medical drugs and how they are tested in drug trials.

Humans have developed a wide range of drugs to help maintain health. Two of the most commonly used are painkillers and antibiotics but there are many others - antiinflammatory, steroids, anti-cancer and heart drugs to name but a few. Scientists are continually developing new drugs but when new medical drugs are devised, they have to be extensively tested and trialled before being used. It can take several years from developing the drug to using it on patients. They are tested in a series of stages to find out if they are safe and effective. New drugs are extensively tested for toxicity, efficiency and dose.

How exactly are drugs tested? Well, the first stage takes place in a laboratory where drugs are tested on cells, tissues and live animals. If they pass those tests, clinical trials take place using volunteers. The doses are gradually increased until the best is found. These trials are carried out under controlled conditions.

During the 1950s, a drug was developed as a sedative or sleeping pill. It was called thalidomide. It was subsequently sold to pregnant women suffering from morning sickness. A lot of these women then gave birth to children whose limbs had not developed properly, around half of the children subsequently died. Thalidomide was taken off the market. How did this happen? It was only tested for its efficiency as a sedative and was assumed to be safe. It is now just used to treat certain types of cancer and leprosy. Following this terrible error, drug testing rules were made much stricter.

What is a placebo?
A double strength version of a drug
A half strength version of a drug
A fake version of the drug
A scientist who specialises in doing clinical trials
A placebo is a control to make the results more accurate. If a volunteer who took a placebo reports that they have recovered or are feeling better, it means that their result can be ignored as they have not taken the drug
What is the purpose of the first clinical trial?
To see if it is toxic to humans
To find the best dose
To make some money so that they can manufacture the drug
To see if people like the taste of the new drug
If the drug is found to be non-toxic, a second clinical trial can be carried out to find the best dose and to see just how effective it is
What is the importance of thalidomide?
It was the first ever antibiotic
It prompted drug testing laws to be improved
It was the most profitable drug of all time
It was the first drug to be sold that didn't need a prescription
It was never tested for use on pregnant women. At the time, the medical profession still didn't realise how easily a foetus could be damaged. Women at the time even smoked cigarettes and drank alcohol whilst pregnant
Which one of the following is not a medical drug?
The difficulty with this question is making the choice between heroin and LSD. The chemical name for heroin is diacetylmorphine and it is used in UK hospitals as an extremely powerful pain killer
Which of these is one reason why it costs a lot of money to develop new drugs?
A lot of the new substances being developed as drugs fail the first tests
It makes the drugs companies more profit
They pay large sums of money to people who agree to take part in clinical trials
Making the placebo costs twice as much as making the new drug
It takes a lot of work by teams of scientists to come up with ideas for new drugs. Then they have to work out how to make the new chemical which isn't easy. This all costs a lot of money and that is before the first trial so if a lot of the substances they develop fail any of the tests, that is a lot of money spent for no result
Why was thalidomide sold to pregnant women?
To cure backache
To prevent varicose veins
To help them sleep
To stop morning sickness
The 'catch' here would be the answer 'to help them sleep' as that was the original use of this drug
Why must medical drugs be tested before they are used on patients?
To check they work efficiently
To check that they are safe to use
To find the best dose
All of the above
Testing can also find any side-effects that taking the particular drug might have
Why are drugs tested on cells, tissues and live animals in the laboratory first?
Only to see if it does what the scientists hope it will do
Only to find out if it could be toxic
Only to check for the right dose
To see if it if it works and is non-toxic
The drugs are tested using computer models and human cells grown in the laboratory. Many new drugs fail this test because they damage the cells or do not seem to work. Only if they pass this test will testing be taken further
What is a double blind clinical trial?
One in which the patients wear blindfolds so they don't know if they have had the drug or the placebo
Only the doctors know who has had the drug and who has had the placebo
Only the patients know who has had the drug and who has had the placebo
Neither the doctors nor the patients know who has had the drug and who has had the placebo until afterwards
This makes the results of clinical testing more accurate
What were the effects of thalidomide on a foetus?
Twisted spine
Limb abnormalities
Kidney problems
Uneven growth of the head bones (elephantitis)
Many of the thalidomide children also had abnormalities with their internal organs, which is why such a high proportion died
You can find more about this topic by visiting BBC Bitesize - Treating, curing and preventing disease - AQA

Author:  Kev Woodward

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