Trial by Science

Trial by Science

Before a new medicine reaches a pharmacy it faces years of testing, designed to answer two questions: is it safe, and does it work? Many drugs started out extracted from plants and microorganisms: • Digitalis: a heart drug from foxgloves. • Aspirin: a painkiller from willow bark. • Penicillin: the first antibiotic, discovered by Alexander Fleming from the Penicillium mould. This module follows a drug from its source through preclinical testing and human trials to approval.

Name the source

The antibiotic penicillin was originally discovered from what?

• A mould, discovered by Alexander Fleming
• The foxglove plant
• Willow bark
• An animal

Three questions

Every potential new drug is tested for three things, and the exam wants the term, not the paraphrase:

Match the terms

Two stages of testing

Testing runs in two big stages, and a question naming one rarely wants the other. Safety always comes before dose: you never give a large dose until you know it is not toxic.

Order the testing

Put the stages of testing a new drug into the correct order, from first to last.

• Test on cells and tissues in the lab
• Test on live animals
• Test on healthy volunteers at a very low dose
• Test on patients to find the optimum dose

Removing bias

To trust the results, trials are designed to remove bias: • A placebo is a dummy treatment with no active drug. Some patients get it so the drug's effect can be compared fairly. • In a double-blind trial, neither the patients nor the doctors know who got the real drug. so expectations can't sway the result. • Finally, results are peer reviewed: checked by other scientists before publication. To catch false claims.

Who knows?

In a double-blind trial, who knows which patients are getting the real drug rather than the placebo?

• Neither the patients nor the doctors
• Only the doctors
• Only the patients
• Everyone is told

Complete the process

New drugs are first tested in the lab on cells, tissues and _____, then in clinical trials on human _____. To remove bias, trials are often _____.

True of clinical trials?

Pick the TWO correct statements about clinical trials.

• Healthy volunteers are tested first, at low doses, to check safety
• In a double-blind trial neither doctor nor patient knows who got the real drug
• New drugs skip lab testing and go straight to patients
• Patients are always told immediately if they got the placebo

Design the trial

A new drug has passed preclinical testing. You are designing the human trial. Make three decisions.

• Who receives the drug first, and at what dose?
• Half your patients improve. How do you show the drug caused it?
• Your doctors know which patients got the real drug, and you are worried it is colouring their assessments. What do you change?

Explain the order

Explain why a new drug is given to healthy volunteers at a very low dose before it is ever given to patients. Take the reasoning through to what would go wrong otherwise.

• Say which of the three questions the first stage is trying to answer
• Say why a low dose is used rather than the dose you hope will work
• Say what the risk would be if patients were given a full dose first

In the exam

Trial complete. Grade-9 habits for drug development: • Drugs are tested for toxicity, efficacy and dose: safety first, always. • Preclinical = cells, tissues, animals; clinical = healthy volunteers then patients. • Placebo and double-blind remove bias; peer review checks the results before they're published.