4.3.1.9 Discovery and Development of Drugs

Question 1

How were drugs initially discovered and extracted?

Answer 1

drugs initially discovered and extracted from plants and microorganisms

Question 2

How can plants be used to treat symptoms of human diseases?

Answer 2

the chemicals that plants use to kill pests and pathogens can be used to treat symptoms of human diseases

Question 3

Drugs that were initially extracted from plants and microorganisms:

Answer 3

• heart drug digitalis originates from foxgloves
• painkiller aspirin originates from willow
• penicillin was discovered by Alexander Fleming from the Penicillium mould
  
  • Alexander Fleming was growing bacteria on plates
  • he found mould (Penicillium mould) on his culture plates, with clear rings around the mould indicating there was no longer any bacteria there
  • he found that the mould was producing a substance called penicillin which killed bacteria

Question 4

How are new drugs developed today?

Answer 4

• new drugs mainly synthesised by chemists in the pharmaceutical industry
• need to be tested for toxicity, efficacy (how well they carry out their role) and dose using preclinical testing and clinical trials

Question 5

What are new drugs extensively tested for?

Answer 5

new drugs extensively tested for toxicity, efficacy and dose

Question 6

Placebo:

Answer 6

A substance designed to be indistinguishable from a drug being tested but has no actual effect on the patient

Question 7

Placebo effect:

Answer 7

when a patient is given a placebo causing them to have the expectation that they’re symptoms will reduce - optimistic mindset may cause symptoms to reduce

Question 8

Biased:

Answer 8

to feel/show inclination or prejudice for against someone/something

Question 9

Risks of taking part in a drug trial:

Answer 9

• permanent effects e.g. permanently handicapped
• brain damage
• organ failure
• could be addictive
• death

Question 10

What are the phases of drug testing and development?

Answer 10

1. Discovery and development
2. Preclinical testing
3. Clinical testing
4. FDA Review
5. FDA Post-Market Safety and Monitory

Question 11

What happens in the discovery and development phase of drug testing?

Answer 11

• Research for new drug begins in laboratory
• Synthetic chemicals:
  
  • chemists produce a wide range of new chemicals every yr
  • many screened for useful medical effects
  • sometimes chemists use computer models to design a molecule which should cure an illness
  • then they try to make it in lab to se if it works as predicted (preclinical testing)

Question 12

What happened in the preclinical testing phase of drug testing and development?

Answer 12

• uses cell cultures or body parts (in vitro screening) tested for toxicity, efficacy (how well they carry out their role) and dosage
  
  • uses cells, tissues and live animals

Question 13

What happens in animal testing (part of preclinical testing)?

Answer 13

• the few chemicals that pass in vitro screening move onto whole animal testing
• scientists think drug is safe but need to check on living body
• at this stage scientists learn how drug works in a living body

Question 14

Advantages of animal testing:

Answer 14

• animal testing has helped to develop vaccines against diseases like rabies, polio, measles, mumps, rubella and TB
• scientists claim there are no differences in lab animals and humans that cannot be factored into testing
• antibiotics, HIV drugs, insulin and cancer treatments rely on animal tests - other testing methods aren’t advanced enough
• operations on animals helped to develop organ transplant and open heart surgery techniques

Question 15

Disadvantages of animal testing:

Answer 15

• different to a human’s
• animals are still used in test items like cleaning products which benefit mankind less than medicines or surgery
• successful alternatives include test tube studies on human tissue cultures statistics and computer models
• stress that animals endure in labs can effect experiments making the results meaningless

Question 16

What happens in clinical testing (Phase I - Human Trials: Testing on Volunteers)?

Answer 16

• clinical trials
• first tested on healthy volunteers with low dose to ensure there are no harmful side effects
• can monitor for safety and side effects
• tests for toxicity
• double blind trial + use of placebo which does not contain the drug
• animal test continue, looking for long-term effects

Question 17

What happens in clinical testing (Phase II - Human Trials: Testing on Patients)?

Answer 17

• this is where scientist can see if drug will be safe and effective
• drugs then tested on patients to find optimum dode for drug
• to test how well drug works, patients split into 2 groups with 1 group receiving the drug and one receiving a placebo (appears to look like drug but has no active ingredient so no effect) so effect of new drug can be observed
• these can be single-blind (only the doctor knows whether the patient is receiving the drug) or double blind (neither doctor knows whether they are receiving the drug, removing the biases the doctors may have when recording results) - removes bias
• results then need to be peer reviewed by other scientists to check for accuracy and repeatability + to help prevent false claims

Question 18

What happens in clinical testing (Phase III - Human Trials: Final Tests and Linking)?

Answer 18

• trial moves to phase III if all goes well in phase II
• many more people given drug
• some of people in phase II will be given a placebo so doctors can compare effect of drug with already available medicines or nothing at all
• by end of successful phase III the drug company submit its research to government bodies to ask for license to sell drug

Question 19

What happens in clinical testing (Phase IV - Human Trials:Post-Market Monitoring)?

Answer 19

• even once medicine has been licensed for use it is still watched carefully for unexpected problems
• these phase IV trials where doctors report any side effects suffered by their patients is continues as long as medicine is used
• phase IV trials can involve 100,000s of people
• sometimes the trials throw unexpected problems - medicines can be withdrawn from use if serious problems appear
• a drug company may decide to develop a new drug with fewer side effects starting the process again

Question 20

What happens in the FDA review phase of drug testing and development?

Answer 20

FDA review teams thoroughly examine all of the submitted data related to the drug or device and make a decision to approve or not to approve it

Question 21

What happens in the FDA post-market safety monitoring?

Answer 21

FDA monitors all drug and device safety once products are available for use by the public

Question 22

Double blind trial:

Answer 22

a study performed where neither the researcher or patient know whether the patient os taking the drug or placebo

Question 23

Side effects:

Answer 23

other additional effects that the drug has that are different from the expected effect of the drug

Question 24

How does clinical testing take place?

Answer 24

• clinical trails use healthy volunteers and patients
• very low doses of the drug are given at the start of the clinical trial
• if the drug is found to be safe, further clinical trials are carried out to find the optimum dose for the drug
• in double blind trials, some patients are given a placebo

Question 25

How do drugs affect our bodies?

Answer 25

drugs affect our body chemistry

Question 26

Why may people take drugs?

Answer 26

• drugs may be used recreationally as people like the effect on the body - some drugs are addictive
• some athletes take drugs to improve performance

Question 27

When can people make sensible decisions about drugs?

Answer 27

people cannot make sensible decisions about drugs unless they know the full effects of them

Question 28

Types of drugs:

Answer 28

• Medical drugs:
  
  • Prescribed - a doctor must provide a prescription for these to be obtained e.g. antibiotics and strong painkillers such as morphine
• Recreational drugs:
  
  • Legal - e.g. alcohol, caffeine, nicotine
  • Illegal - e.g. ecstasy, cannabis and heroin

Question 29

Preclinical drug testing:

Answer 29

drug testing done in laboratory using cells, tissues and live animals

Question 30

Thalidomide:

Answer 30

drug that was developed as a sleeping pill

Question 31

What was thalidomide found to be effective in?

Answer 31

relieving morning sickness in pregnant women - but not tested for this use

Question 32

Why was thalidomide banned and what did this cause?

Answer 32

• many babies born to mothers who took the drug were born with severe limb abnormalities
• drug banned
• as a result drug testing become much more rigorous

Question 33

What has thalidomide been successful in the treatment of?

Answer 33

thalidomide has been used successfully in the treatment of leprosy and other diseases

Question 34

Statins:

Answer 34

relatively new group of drugs used to lower blood cholesterol levels

Question 35

What does a high cholesterol level increase the risk of?

Answer 35

increases a person’s risk of having heart attack or stroke

Question 36

What does the long-term use of statins reduce?

Answer 36

long-term use of statins reduces the risk of having a heart attack or stroke and increases the life expectancy of people with a history of heart disease

Question 37

Why are people concerned about the use of statins?

Answer 37

concerned that these drugs could encourage people to lead an unhealthy lifestyle in the belief that they can reduce their cholesterol levels