Biology 1 Testing drugs Drugs Trials……. Would You?????

Biology 1 Testing drugsBiology 1 Testing drugs


Drugs Trials…….

Would You?????


Want to earn some money??

Two thousand pounds only2,000

6th July 2007

S. Martin

Fred Bloggs


Thalidomide


Thalidomide – the sleeping pill


• Thalidomide was first synthesized in West Germany in 1953 by Chemie Grünenthal.

• It was hailed as a "wonder drug" that provided a "safe, sound sleep".


• However the drug was also found to cure morning sickness in pregnant women


Nausea vomiting in pregnancy NVP – 1st trimester ...(1/3)


Foetal development -

• The first few weeks are a key period – any problems now will accumulate in the future


Nausea vomiting in pregnancy NVP – 1st trimester (1/3)

• When do you think most women would be inclined to take this drug?


Side effects

• unfortunately molecules of the thalidomide chemical crossed the placenta and disrupt the growth patterns of the growing foetus


Effect = catastrophic deformations of the baby– best seen as limb abnormalities.


…if this was you – how would your life be different?


Why did this happen?

• Simple - the drug was not trialled or tested for this use on pregnant women


Thalidomide today

• Initially the drug was banned internationally for the treatment of morning sickness

• But it has now been reintroduced as a treatment for leprosy


Leprosy – bacterial infection of the skin and nerves endings

• Affects the hands, feet and features of the face.


Leprosy


Pfizer LtdPfizer Ltd

Drug testing sequenceDrug testing sequence

How are new drugsHow are new drugsdeveloped?developed?


Synthetic chemicals?

First tests in laboratory

Animal testing

Phase I: Testing on students!

Phase II: Testing on patients

Phase III: Final tests and licensing

Which diseases to treat?

Traditional remedies?

Drug Development

and Testing


Which diseases to treat? Doctors, politicians, drug company executives, members of the public and scientists all have an opinion. At some point money will be made available for the research into a disease cure to begin.


Traditional remedies? Where to start? Sometimes researchers will look at ‘traditional remedies’ to see if there is anything to learn. Plants, animals, bacteria and fungi have all been used as sources for new medicines.


Synthetic chemicals?Chemists produce a wide range of new chemicals every year. Many

are 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 the laboratory to see if it works as predicted.



First tests in laboratoryThe first level of testing uses cell cultures or body parts (in vitro screening). The potential medicine is tested thoroughly to answer the questions ‘Is it toxic (poisonous)?’ and ‘Does it work?’



Animal testingThe few chemicals that pass the first stage move on to whole animal testing. We think the drug is safe but we need to check. At this stage scientists also learn about how the drug works in a living body.


Phase I Human trials: testing on volunteersThe (very few) chemicals that pass the animal testing stage move on to the first human tests. These are done on healthy people – often students who get paid a small amount of money for volunteering. This stage checks the safety of the drug and looks for side effects. Animal tests continue, looking for any long term effects.


Phase II: Testing on patientsThe first ill people to get the drug are the Phase II volunteers. This is where scientists can really begin to see if the drug will be safe and effective.


Phase III: Final tests and licensingIf all goes well with phase II the trials move to phase III. Many more people are given the new drug. Some of the people in the phase III trial will be given dummy treatment so that doctors can compare the effect of the drug with already available medicines or nothing at all. By the end of a successful phase III the drug company submits its research to government bodies to ask for a licence to sell the drug.


Even once a medicine has been licensed for use it is still watched carefully for unexpected problems. These phase IV trials, where doctors report on any side effects suffered by their patients, continue as long as the medicine is used. Phase IV trials can involve hundreds of thousands of people.

Sometimes the trials throw up unexpected problems - medicines can even be withdrawn from use because serious problems appear! A drug company may decide to develop a new drug to replace the original one because it has fewer side effects. The whole process begins again!

Peninsula Medical SchoolPeninsula Medical School

Biology 1 Testing drugs Drugs Trials……. Would You?????

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