New medicines

Question 1

What are medicines?

Answer 1

chemicals that are used to treat the cause or signs of an illness

Question 2

What is a placebo?

Answer 2

for comparison/ a fake drug containing no real medicine

Question 3

What are the different steps of testing?

Answer 3

Discovery/computer/lab testing
Animal testing
Clinical trials stage 1
Clinical trials stage 2
Clinical trials stage 3
Clinical trials stage 4

Question 4

What happens during computer/lab testing?

Answer 4

Medicines are discovered by screening organisms to see if they produce antibiotics that kill bacteria.

The antibiotics are then tested on human cells to ensure that the medicine gets into cells without harming them, and damages the pathogens.

Most drugs never make it past this stage.

Question 5

What happens during animal testing?

Answer 5

The drug is tested on animals to make sure that it is safe and doesn’t harm the animals.

Question 6

What happens during clinical trials stage 1?

Answer 6

Healthy volunteers are given a small dose of the drug.

Small number of volunteers (about 10)

The drug is tested for side effects and to check that it is not toxic/harmful.

The optimum dose is found.

Question 7

What happens during clinical trials stage 2?

Answer 7

Small number of people (100)

Often with advanced stages of a disease

The purpose is to find the correct dose of the drug, and to test it if works.

Efficacy (whether it works)
Optimum dose

Placebos are used for comparison

Question 8

What happens during clinical trials stage 3?

Answer 8

A bigger number of people (1000s)

Testing how well the drug works against similar drugs.

Testing how well it works.

Looking for side effects.
Finding the best dose.

Might be blind or double blind.

Question 9

What happens during clinical trials stage 4?

Answer 9

Done after the drug has been shown to work and has been granted a licence.

Finding out the long term risks and benefits

More about side effects and safety

How well the drug works when used more widely

Tested on the general population

Question 10

What is an open trial?

Answer 10

When both the patient/volunteer and the medical team know whether the drug is a placebo or real.

This happens rarely, or when the patient is in an advanced stage of illness.

Question 11

What is a blind trial?

Answer 11

When the medical/research team knows if the drug is real but the volunteer doesn’t.

This can lead to the research team giving away clues, observer bias.

Question 12

What is a double-blind trial?

Answer 12

When neither the medical team or the patient know if the drug is real or a placebo.

Question 13

Explain why a new medicine is not tested on lots of people straight away.

Answer 13

This is to make sure that there are no harmful side effects and also to make sure it works on people.

It would be unethical to give the medicine to lots of people before it was tested for safety and to see if it works on people.

Question 14

There are two antibiotics, A and B, that are effective against a particular bacterial infection.

Antibiotic A produces a larger clear zone around it than antibiotic B when tested on a petri dish of bacteria.

However, the doctor chooses to prescribe antibiotic B to the patient.

Give two possible reasons for this.

Answer 14

B may be cheaper

A may have side effects

patient may be allergic to A

A may not be suitable for pregnant woman

A may not be compatible with other drugs that the patient is taking

Question 15

What is the clear zone around an antibiotic in a petri dish called?

Answer 15

the zone of inhibition

Question 16

Why is it important to finish a full course of antibiotics?

Answer 16

in a bacterial infection, different bacteria have different levels of resistance to antibiotics

the ones that aren’t as resistant will die first, this may lead to the patient believing that the disease has gone

however, a small amount of antibiotic resistant bacteria will still remain

if the patient finishes all the antibiotics, all of the bacteria will die

if they don’t, the small amount of resistant bacteria that are left will multiply and the disease will return

the same antibiotic will no longer be able to treat the disease effectively

if the patient passes that strain of the disease on, others may catch it and that particular antibiotic will end up becoming unusable to treat that particular disease

Question 17

Suggest one advantage and one disadvantage of using animals as models for testing new drugs rather than direct testing on humans.

Answer 17

An advantage is that drugs can be tested for safety without harming humans.

A disadvantage is that the drugs may not work the same way in the animal as they would in a human.

Many people are also against the use of animals for testing.

Question 18

Clinical trials are expensive and take a long time to complete.

Drugs have to pass each stage of testing before they can move on. If they fail a stage, they are no longer tested.

State two advantages and two disadvantages of this method.

Answer 18

Advantages:

• unsafe drugs aren’t given to people
• if a drug fails early on it saves time and money
• drugs that aren’t effective aren’t used

Disadvantages:

• if there is an outlier result in a small group of people, the drug might be discontinued despite being effective
• if a drug fails later on, a lot of time and money will have been wasted