6.4 Developing drugs

Question 1

Testing new drugs can cost alot of money and take up to 12 years.

Draw a flow chart to show the main stages in testing new drugs (6 marks)

Answer 1

flow chart should include:
identify pathway in disease that needs cure
→ identify new chemical (in living organisms or lab)
→ preclinical testing on cells, tissues, and animals
→ phase 1 clinical trials check for side effects
→ phase 2 clinical trials check efficacy and safety
→ phase 3 clinical trials check efficacy, safety, and dosage → licencing
→ phase 4 clinical trials monitor safety throughout life of drug

Question 2

Explain why an active drug is used as a placebo in a clinical trail instead of a sugar pill that has no effect
3 marks

Answer 2

If there is already a drug available for treating a disease it would be unethical to deprive patients of treatment by giving a placebo that would have no clinical effect.

If new drug is for a condition where there is a current treatment, patients will be given best current treatment as placebo.

This is ethical and provides comparison between new drug and current best practice.

Question 3

Florey and Chain tried penicillin on a human volunteer without preclinical trails. Thalidomide was used without any proper testing and caused limb deformities in developing foetuses. The outcomes were very different.

Discuss the need for full trailing of all drugs and consider how and why the process has changed over time

Answer 3

• Florey and Chain successfully treated their patient although drugs ran out before he was fully cured.
• The next patient they tried it on was cured.
• Thalidomide resulted in the birth of many thousands of babies with no limbs or very much shortened limbs.
• Trial process has changed over time (more treatments are now available, allowing luxury of time to fully test new ones, which was not the case for Florey and Chain time).
• Thalidomide outcomes show that it is important to test new drugs on pregnant animals as well as healthy adults.

Question 4

Define toxicity in regards to drug testing

Answer 4

toxicity: whether a drug is toxic and, if so, how much of it is has to be
given to have a toxic effect

Question 5

Define dosage in regards to drug testing

Answer 5

dosage: dose of a drug that is effective in treating a disease

Question 6

Define efficacy in regards to drug testing

Answer 6

efficacy: whether a drug does the job it is designed to do

Question 7

Why are drugs tested and trialed before use?

Answer 7

make sure it works well and ios safe

Question 8

A good medicine is …. (4 things)

Answer 8

• effective
• safe (not toxic or have side effects)
• stable (can be stored under normal conditions and for some time)
• successful

Question 9

What is preclinical testing of a drug?

Answer 9

Takes place in in the laboratory using cells, tissues and live animals

Question 10

What is clinical testing?

Answer 10

Using healthy volunteers or patients. First low doses are given to healthy people to check for side effects. If it is safe its tried on a small number of patients to see if it treats the disease. If its safe and effective bigger clinical trails occur to find optimum dosage

Question 11

What is a placebo?

Answer 11

medication that doesn’t contain the trial drug

Question 12

What is double blind trial?

Answer 12

Some patients are given the new medicine and others are given a medicine that doesn’t contain the drug.

Doctor and Patients health is monitored carefully.
patient don’t find out who had what until the trial is over.