Testing diseases Flashcards
What are antibiotics? (Example):
- Medicines which kill bacteria inside the body e.g. penicillin.
- Doctors will prescribe certain antibiotics for certain diseases
What can antibiotics NOT destory?
- Viruses
What has antibiotics greatly reduced? However…
- Deaths from infection
- However bacterial strains resistant to antibiotics are increasing e.g. MRSA
How do you reduce the rate at which resistant strains of bacteria develop?
- Doctors should NOT prescribe antibiotics UNLESS:
- they are really needed
- for non-serious infections
- for viral infections
- **Patients MUST complete their course of antibiotics so that all bacteria are killed and none survive to form resistant strains
Why is there a constant demand to produce new drugs?
- New painkillers are developed to treat the symptoms of disease but, they do not kill the pathogens.
- Antiviral drugs are needed that will kill viruses without also damaging the body’s tissue
- New antibiotics are needed as resistant strains of bacteria develop.
Drugs extracted by plants and microoganisms:
- Digitalis - a heart drug which originates from FOXGLOVES
- Aspirin - a painkiller which originates from WILLOW
- Penicillin - discovered by Alexander Fleming from the PENICILLIUM.
How are most new drugs created?
- Most new drugs are synthesised by chemists in the pharmaceutical industry
- However, the starting point may still be a chemical extracted by a plant
What has to happen to medical drugs before being used?
- Tested and trialed
- This is to ensure that the toxicity, effectiveness and dosage is safe
What is the first stage in testing drugs?
Computer trials:
- The drugs are tested using computer models and skin cells grown using human stem cells in the laboratory.
- This allows the efficacy and possible side effects to be tested.
- Many substances fail this first test of a preclinical drug trial because they damage cells or do not seem to work.
What is the second stage in testing drugs?
Preclinical trials:
- Drugs that pass the first stage are tested on animals in the second part of a preclinical drug trial.
- In the UK, new medicines have to undergo these tests.
A typical test involves giving a known amount of the substance to the animals, then monitoring them carefully for any side-effects.
What is the third stage in testing drugs?
- Drugs that have passed animal tests are used in human clinical trials.
- They are tested on healthy volunteers to check that they are safe.
- The substances are then tested on people with the illness to ensure that they are safe and that they work.
-Low doses of the drug are used initially, and if this is safe the dosage increases until the optimum dosage is identified.
What is a double-blind trial?
- Some patients are given a placebo, which does not contain the drug, and some patients are given the drugs.
- Patients are allocated randomly to the two groups. NEITHER the PATIENT or the DOCTOR know who has received the placebo or the real drug.
- This is done to make the study less likely to be biased.
