AQA · GCSE · Combined Science

    Course version: 8464 · Version from Sept 2018

    Very low doses of the drug are given at the start of the clinical trial.

    Full specification wording

    Discovery and development of drugs: Very low doses of the drug are given at the start of the clinical trial.

    Clinical trials test a new drug on humans only after laboratory and animal testing.

    Checked against the AQA 8464 specification (opens in a new tab) on .

    • Point 11 of 13

    Study notes

    From the checked teaching notes for this specification point.

    The idea

    Clinical trials test a new drug on humans only after laboratory and animal testing. At the start, volunteers receive very low doses. This is a safety precaution: humans may react differently from animals, and a low dose limits any harm while still allowing researchers to observe the drug's effects. For example, a trial might begin with a dose of a few milligrams and then increase it gradually in later stages. Starting low also helps scientists gather early data on how the body absorbs and removes the drug. If unexpected side effects appear, the trial can be stopped before anyone receives a larger dose.

    What earns the marks

    • Very low doses are used at the start of a clinical trial to reduce the risk of harm to human volunteers.
    • The first human doses are given only after earlier laboratory and animal testing has been completed.
    • Starting with a low dose allows researchers to observe effects and side effects before increasing the dose.
    • Dose escalation is gradual, so any unexpected reaction can be detected and the trial stopped.
    • Low starting doses help establish how the human body handles the drug, including absorption and removal.

    Common mistakes and how to put them right

    • Thinking clinical trials begin with the full intended dose.

      Put it right by stating that very low doses are given first and increased gradually.

    • Confusing clinical trials with animal testing.

      Put it right by noting that clinical trials involve human volunteers and follow earlier laboratory and animal tests.

    • Assuming a low dose proves the drug works.

      Put it right by explaining that early low doses mainly check safety and effects, not effectiveness.

    Exam tips

    • Link the low starting dose directly to safety, using words such as 'reduces risk of harm' or 'limits side effects'.
    • State clearly that the dose is increased gradually rather than jumping to the therapeutic dose.
    • Use the phrase 'clinical trial' accurately to mean testing on humans, not animals or cells.

    Try the lesson

    The start of the Discovery and development of drugs: Very low doses of the drug are given at the start of the clinical trial. lesson, made from checked teaching notes for this specification point.

    Have a go first

    Why are very low doses of a new drug given at the start of a clinical trial?

    Listen

    Clinical trials test a new drug on humans only after laboratory and animal testing. At the start, volunteers receive very low doses. This is a safety precaution: humans may react differently from animals, and a low dose limits any harm while still allowing researchers to observe the drug's effects. For example, a trial might begin with a dose of a few milligrams and then increase it gradually in later stages. Starting low also helps scientists gather early data on how the body absorbs and removes the drug. If unexpected side effects appear, the trial can be stopped before anyone receives a larger dose. A strong answer earns marks for these points. Very low doses are used at the start of a clinical trial to reduce the risk of harm to human volunteers. The first human doses are given only after earlier laboratory and animal testing has been completed. Starting with a low dose allows researchers to observe effects and side effects before increasing the dose. Dose escalation is gradual, so any unexpected reaction can be detected and the trial stopped. A common slip: Thinking clinical trials begin with the full intended dose. Instead, stating that very low doses are given first and increased gradually. Exam tip: Link the low starting dose directly to safety, using words such as 'reduces risk of harm' or 'limits side effects'.

    See it

    A top-down flowchart. The first box says laboratory and animal testing completed, with an arrow to a box saying clinical trial begins with human volunteers. An arrow leads to a box saying very low doses given at the start, then to a box saying researchers observe effects and side effects. From there, one arrow leads to a box saying dose increased gradually in later stages, and another arrow leads to a box saying unexpected side effects appear, which leads to a final box saying trial can be stopped before a larger dose is given.
    It shows the sequence of a clinical trial, from earlier laboratory and animal testing through very low starting doses, gradual dose increase, and stopping the trial if unexpected side effects appear.

    Label the diagram

    Some boxes have lost their names. Pick the right name for each number.

    The diagram again, with 3 boxes numbered instead of named. A top-down flowchart. The first box says laboratory and animal testing completed, with an arrow to a box saying clinical trial begins with human volunteers. An arrow leads to a box saying very low doses given at the start, then to a box saying researchers observe effects and side effects. From there, one arrow leads to a box saying dose increased gradually in later stages, and another arrow leads to a box saying unexpected side effects appear, which leads to a final box saying trial can be stopped before a larger dose is given.

    • 1Box 1

    • 2Box 2

    • 3Box 3

    0 of 3 labelled

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