Bonjour: Biology Unit 1 Topic 3

Biology Unit 1 Topic 3

Drugs
Drugs are substances that change chemical reactions in the body.
Medical drugs relieve diseases and illness.
Recreational drugs are used for pleasure.

Developing new drugs
1. Drugs are tested using computer models and human cells growth in the laboratory. (Many substances fail this test as they damage the cell or don’t work)
2. Drugs that pass the first stage are tested on animals. They are monitored carefully for any side effects.
3. Drugs that passed the animal test are used in clinical trials. They are tested on healthy volunteers to check if they are safe. Low doses are used at the beginning and further clinical trials are done to find the optimum dose for the drug.
Clinical trials are not without risk and severe side effects may occur.

Double blind trials

People feel better from a drug because they have taken a medicine called a placebo effect.
Double blind trials are used to minimise the placebo effect.
Some people are given the drug whilst others are given a placebo.
A placebo does not contain the drug.
Doctors and patients are both not told which have taken the placebo or drug until the trial is over.

Thalidomide is medical drug that caused an unexpected and serious damage to unborn babies.
First developed as a sleeping pill, it was thought to be useful for easing morning sickness but hasn’t been tested for use in this way.
It was found to have damaged the development of unborn babies, it lead to babies born very short or incompletely formed. More than 10,000 babies were affected around the world.
Thalidomide was banned and drug testing was made more rigorous than before.
Thalidomide is used as a treatment for leprosy and bone cancer now.

Alcohol and nicotine are legal recreational drugs.
Alcohol is a depressant so it slows down signals in the nerves and brain.
It is addictive and long term effects of alcohol include damages to the liver and brain and it is often the cause of weight gain. Small amounts of alcohol can be relaxing but large amounts lead to aggression and sometimes unconsciousness.

Nicotine is found in tobacco smoke
100,000 people die each year from smoking related illnesses.
It is addictive.
It increases the risk of heart diseases and strokes
Premature birth
Lung cancer, mouth + throat cancer
It deposits tar in the lung.

Illegal drugs
Heroin and cocaine are very addictive, they damage the heart and circulatory system, and cannabis can cause mental illness in some people.

Recreational drugs can damage health indirectly (people spending less money on food to buy drugs)

Injecting drugs through a syringe can lead to HIV.








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