Testing New Drugs (AQA GCSE Combined Science: Synergy: Life & Environmental Sciences): Revision Note

Testing New Drugs

• All new drugs need to be tested and trialled before they can be used in patients

• They are tested for:

  • Toxicity – does it have harmful side effects?

  • Efficacy – does the drug work?

  • Dose – what dose is the lowest that can be used and still have an effect?

• The results of any testing are then peer-reviewed to make sure that the results are described accurately. The results would then be published in journals

Developing New Drugs

• Preclinical testing is done in a laboratory using cells, tissues and live animals

• Clinical trials 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

The 3 stages of drug development

• Preclinical Testing

  • The drug is tested on cells in the lab

  • Computer models may also be used to simulate the metabolic pathways that may be taken by the drug

  • Efficacy and toxicity are tested at this stage

• Whole organism testing

  • The drug is tested on animals to see the effect in a whole organism – all new medicines in the UK have to have tests on 2 different animals by law

  • Efficacy, toxicity and dosage are tested at this stage

• Clinical trials

  • The drug is tested on human volunteers first, generally with a very low dose then increased. This is to make sure it is safe in a body that is working normally

  • The next stage is to test on patients with the condition.

    The patients are often split into two groups; one given the drug the other given a placebo. This is called a double-blind study – neither the doctor nor the patient knows if the patient is getting the placebo or the active drug

  • Once the drug is found to be safe then the lowest effective dose is tested at this stage

Future medications

• Pharmaceutical companies are always looking to find new medications these include:

  • Vaccinations to different diseases

  • Antibiotics that have a different action on the bacteria, so that bacteria are not resistant to them

  • Painkillers with fewer side effects

  • Antiviral drugs that don’t damage the body’s tissues

• Sources of these medications may be plants or microorganisms