4 Flashcards
Pharmacokinetics definition
The study of the change in drug and metabolite concentrations in tissues and body fluids
Or
What does the body do with a drug
Why should we make an effort to undertand pharmacokinetics?
So we can get drugs to their site of action…
- Above the therapeutic concentration
- Below a toxic concentration
- ie. Inside the ‘therapeutic window’
Also we may want the drug to not be in the body for a very long time.
What is the therapeutic ratio
Learn what a good ratio is
What does ADME stand for? Why is it important?
- Drug development
- Understanding toxicity
- Establishing route of administration
- Establishing drug dose
- Understanding possible drug interactions
What does bioavailability mean. How is it decreased (learn examples and what 0% and 50% looks like)
The fraction of unchanged drug that reaches systemic circulation.
It is decreased by poorer absorption, first pass metabolism (?)
Note : IV Drug delivery has 100% bioavailability
What does absorption depend on?
- Route of administration
- Chemical nature of compound : lipophilicity (higher the better), charge (uncharged is faster), size (smaller, faster)
- Formulation
- Blood flow rate to site of delivery
Examples of Formulation
Which routes of administration are the fastest to slowest
What is intravenous administration and how effective is it? (google how each of these happen)
Fast but invasive with infection risk
What is intramuscular / subcutaneous administration, and how effective is it?
fairly fast, but invasive/painful and can cause local reactions; can be slowly absorbed in the case of a lipophilic drug injected in lipid
SUblingual, orally, transcutaneous
Between cells or through cells, ease of this depends on physical and chemical nature of the drug
