Lecture 5: Does This Drug Really Work? Flashcards
What occurs during Phase I of drug research?
- Small cohort of patients (20 - 100)
- Study how well tolerated the drug is and what are the pharmacokinetic properties of the drug
- Patients are given a few different doses to determine this
- See if patients experience any adverse side affects
What occurs during Phase II of drug research?
- 100 - 200
* Addresses efficacy: See if any patients derive benefit from the drug
What occurs during Phase III?
- 1000 - 6000 patients
- Randomized control trials where patients receive placebo and drug
- Both patients and clinicians are blind
- If drug sees some benefit it will be approved
What studies occur after the phase III trials?
The drug will still continue to be monitored after being released
What are Clinical trials?
Controlled human studies to assess dosage, administration, safety, efficacy
What is tested in phase I?
- Tolerable dosing ranges
- Bioavailability
- Excretion
What is tested in phase II?
- Efficacy
* Safety in greater numbers
What is tested in Phase III?
•Double blinded trials against placebo
Which phase tests for pharmacokinetics?
Phase I
What are Meta-analyses?
An approach to combine data from multiple trials often after a drug has been approved
How are meta-analyses often displayed?
As forest plots
What is an event on a metaanalysis?
The amount of times an outcome occurs such as a patient getting diabetes
What data does Statin plots provide data on?
- Number of trials
- Size of each trial
- Outcomes of trials
- Overall summary of all trials
What is the Odds Ratio?
The ratio of the event rate in treatment vs control (which one is favored in individual trials vs overall)
What characteristics must a drug have for it to be useful?
It must have a beneficial effect but must also be tolerable in terms of toxicity
What is the Therapeutic Index?
The ratio of the median toxic dose and effective dose
What is described using a Quantal Dose-Response Curve?
Effect or toxicity
How is a Quantal Dose Response Curve different from quantitative effect curves?
Quantal Dose Response Curves shows the cumulative number of patients who have a predefined response to a drug
What is the Effective Dose 50?
The dose that 50% of the patients will exhibit some beneficial response to a drug
What is the Toxic Dose 50?
The dose that 50% of the patients will exhibit some adverse response to a drug
Why is it good to have a big difference between the TD50 and the ED50?
Because then there is a bigger window to give patients that are not responding a slightly higher dose
What does a big therapeutic index mean?
It means that the drug is tolerated with minimal toxicity and gives a lot of flexibility for dosing
What is a drawback to the Therapeutic index?
There is a lot of variability in drug response for individuals
What other consideration must be taken into account for effect and toxicity?
Conditions like diet, liver function and kidney function
