Antibiotics and Other Medicines

Question 1

Explain how antibiotics treat bacterial infections in humans.

Answer 1

• Antibiotics prevent the growth of bacterial cells by inhibiting their cell processes
• They do not affect the cells in the host organism

Question 2

Antibiotics are not effective against viruses.

Suggest an explanation as to why it is difficult to develop drugs that target viral pathogens.

Answer 2

• Viruses can only reproduce inside host cells
• This means it is very hard to develop drugs which target the virus but not the cells of the host organism

Question 3

Give the correctly ordered sequence of stages in the development of a new drug.

Answer 3

Preclinical testing:

• Drug first tested on human cells and tissues
• Drug then tested on live animals

Clinical testing:

• Drug tested on healthy, human volunteers if it passes the tests on animals
• It is then tested on a person with the illness if the results of the prior tests are good
• The optimum dose is found
• Placebos and double-blind methods are carried out
• Once a drug has passed all the tests, it has to be approved by a medical agency

Question 4

Give one thing which is investigated during the pre-clinical testing of drugs.

Answer 4

Any of the following:

• Toxicity
• Efficacy
• Dosage

Question 5

Suggest why very low doses of the drug are given at the start of clinical trials.

Answer 5

In case the drug has any harmful effects

Question 6

What is a placebo?

Answer 6

A substance that is like the drug being tested but doesn’t do anything

Question 7

Placebos and double-blind methods are often used in clinical trials.

Explain why placebos are used.

Answer 7

To ensure that any effect of the drug is due to the drug itself and not because the patient is expecting to feel better

Question 8

(Exam-style question)

Answer 8

Question 9

Explain why double-blind trials are used.

Answer 9

So that neither the patients nor the doctors are able to subconsciously influence the results of the trials