3.1.9

Drug Testing

Test yourself

Testing Drugs

New medical drugs have to be tested and trialled before being used to check that they are safe and effective. This testing can take many years and the drugs are tested on three main criteria:

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Toxicity

  • Is the drug safe?
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Efficacy

  • Does the drug work?
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Dose

  • How much of the drug is needed?

Drug Testing in Laboratories

There are 2 stages to drug testing in laboratories:

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Preclinical testing

  • Scientists carry out early stage testing on human cells and tissues grown in the laboratory.
  • Scientists also carry out early stage testing on live animals.
  • Testing on animals is useful for working out how toxic (harmful) a drug is to cells.
  • In the UK, new medicines have to undergo tests on two different live mammals.
  • Many drugs fail at this stage if they damage cells or do not work.
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Clinical testing

  • Clinical trials test drugs on healthy volunteers and patients to check that they are safe. They usually use low doses of the drug.
  • If a drug is found to be safe at low doses, there are more clinical trials to work out the optimum (best) dose for the drug.

Double-Blind Trials

In clinical trials, some patients are given a placebo (an alternative that does not contain any of the drug). Whether a patient gets the drug or the placebo is randomly chosen. Neither the patient nor the doctor knows who has received which.

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Unbiased

  • Double-blind trials make sure that a test is perfectly fair.
  • If either the patient or doctor knew what they were taking, it could skew the outcomes of the trial.
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Identical conditions

  • All the conditions are kept identical across the two groups so that only the drug has an impact on a patient’s health.

Jump to other topics

1Cell Biology

2Organisation

2.1Principles of Organisation

2.2Enzymes

2.3Circulatory System

2.4Non-Communicable Diseases

2.5Plant Tissues, Organs & Systems

3Infection & Response

4Bioenergetics

5Homeostasis & Response

6Inheritance, Variation & Evolution

7Ecology

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