Development of drugs

• Development of Drugs:

  • PRECLINICAL TRIALS - Cells, Tissues and Animals
  • CLINICAL TRIALS - Humans
• PLACEBO


  A tablet that does not contain the drug / active ingredient.

  A fake drug
• Trials are BLIND:

  • so the patient DOESN'T KNOW whether they are taking the real drug or the placebo.
• A PEER REVIEW of the results is studied by other scientists:

  • to ensure the conclusions are correct / valid
  • to prevent false claims from getting published.
  • to avoid bias
• The control variables are:

  • age
  • gender
  • body mass
  • number of children in group
  • time after taking medicine when temperature was measured
  • dose of drug

  
• none of the children was given a placebo as:

  • it's immoral not to treat ill children
  • children were ill so has to be treated
  • children may become more ill if no drug given

  
• The doctors concluded that children with a high body temperature should be given ibuprofen and not paracetamol as:


  • it reduced body temperature faster to normal and maintained it for several hours.
  • decreased body temperature more

  
• Arguments for use:

  • will save the NHS money
  • approximately 20 times as many people can be treated compared to drug A
  • approximately 29 times as many people can be treated compared to Drug B
  • more people can be treated for the same cost
  • patients will be treated sooner
  • improves patient choice
  • used in other countries, so likely to be effective and safe
  • likely to have been tested in other countries

  
• Arguments against use:

  • injections of drug not tested in UK
  • cannot be sure it's as effective as drug A / B or if it's safe to use.
  • may have unknown side effects
  • doctors cannot be confident in prescribing drug C
  • goes against laws on drug development / use
  • might set an example for other drugs not to be fully tested and other non-approved / unlicensed drugs to be used.

  
• Conclusions to be made about the usefulness of the drug to treat asthma:

  • drug only works and increased the lung capacity in severe asthma attacks.
  • It had little effect / slight reduction in healthy people
  • it had no effect in mild asthma attacks
  • It does not reduce the problem entirely

  
• Testing that must be done before a drug can be used to treat people:

  • pre-clinical trials of the new drug on cells / tissues / live animals to test:
  • toxicity
  • dosage
  • efficacy
  • clinical trials on healthy volunteers and patients at very low doses to monitor for safety & side effects
  • and only then do trials to find the optimum dosage and test for efficacy
  • double blind trial / use of placebo (which does not contain the new drug)
  • random allocation of patients to groups, so no one knows who has placebo / the new drug
  • peer review of data to help prevent false claims
• • Alexander Fleming was a microbiologist.
  • One time when he returned to his lab after holiday
  • He noticed that a fungus was growing in one of his petri dishes and it had killed the surrounding colonies of bacteria
  • he found that the fungus produced a substance that was able to kill the bacteria.
  • The type of fungus was penicillium, so he named the substance penicillin.

  
• Efficacy:


  How well it works

  
• Toxicity:


  How harmful the drug is:

  • Potential harm
  • Side effects

  
• Dosage:


  The concentration and how often the drug needs to be taken to give the desired effect.

  • The higher the dose, the higher the efficacy, but also the higher the toxicity.
• PRECLINICAL TRIALS (No humans) - Stage 1:

  Drugs first tests on HUMAN CELLS and TISSUES in the laboratory.

  Advantage:

  • We can easily and cheaply test tons of different substances

  Disadvantage:

  • doesn't tells us how the substance would affect an entire organism or an organ

  Tests on whole or multiple body systems require the use of whole ANIMALS due to their complex circulatory systems.

  
• PRECLINICAL TRIALS (doesn't involves humans) - Stage 2: 


  The drug is tested on live ANIMALS.

  The drug is tested for:

  • EFFICACY
  • TOXICITY

  In Britain, law requires testing on two different LIVE MAMMALS to ensure the drug's safety.

  
• CLINICAL TRIALS - Stage 3:


  HEALTHY VOLUNTEERS are first to receive the drug at low doses, to check for SIDE EFFECTS:

  • The dose is slowly INCREASED and tested, until an max. dosage, without any side effects.

  When that "goes okay", then the drug is given to people suffering from the particular illness that the drug's trying to target.

  • The dose is slowly increased, until an OPTIMUM dosage.
  • When the dose is at:
  • Maximized efficacy
  • Minimized toxicity

  
• CLINICAL BLIND TRIALS - Stage 4:


  To know if the process is fair & results are valid.

  • The drug is delivered to PATIENTS in two groups:
  • One group receives the NEW DRUG.
  • The other group gets a PLACEBO.

  And don't tell them which they're taking, the trial is blind.

  
• Some trials are DOUBLE BLIND:


  Neither the patient nor the monitoring doctors know who received the actual drug or the placebo.

  This reduce bias and prevents the PLACEBO EFFECT:

  • where the patient expects the drug is working, so is subconsciously influenced & reports side effects.
  • Their doctors know who has been given the real drug then they may pay closer attention to those patients.

  Until all the results have been analysed at the end of the study