Drug Absorption Flashcards
What is pharmaceutical process?
Getting the drug into the patient
What is pharmacokinetic process?
Getting the drug to the site of action
What is pharmacodynamics process?
Producing the correct pharmacological effect
What is therapeutic process?
Producing the correct therapeutic effect
What are the 4 basic factors that determine pharmacokinetics?
Absorption
Distribution
Metabolism
Elimination
A knowledge of the factors of pharmacokinetics enables an understanding of what?
Dosage
Drug administration
Drug handling
Patient variability
Potential for harm
What must most drugs do to have biological action?
Enter the blood stream and be distributed to a site of action
What are different methods of administration?
Oral
Intra-venous (IV)
Subcutaneous (applied under the skin)
Intramuscular
Other GI (sublingual, rectal)
Inhalation
Nasal
Transdermal (delivered across the skin)
What is absorption?
Process of movement of unchanged drug from the site of adminstration to the systematic circulation
What does absorption depend on?
Properties of the drug
Dosage used
Anatomy and physiology of the drug absorption site
What is the relationship between plasma concentration and the therapeutic response?
There is a correlation between the two
What is Cmax?
The peak concentration
What is T max?
The time to peak concentration
What does the area under the curve of a concentration/time graph represent?
Total amount of drug that reaches systematic circulation
What does Tmax tell us?
How quickly the drug is going to get into our circulation to produce an effect
What does Cmax tell us?
Whether the effect of a drug may be toxic or ineffective
What does increasing the dose do in relation to Tmax and Cmax?
Does not increase Tmax but increases Cmax
What is the therapeutic range?
The range of concentration that a drug is active
What happens above the therapeutic range?
The drug is toxic
What happens below the therapeutic range?
The drug is ineffective
What is bioavailability?
The amount of a drug that gets into circulation and is available for biological activity
What is the bioavailablity of a drug given intra-venously?
100% bioavailability
How is bioavailability determined?
By giving the drug and working out the toal amount over time then comparing this to the IV route
What are some factors that affect bioavaiability?
Formulation
Ability of drug to pass physical barriers
Gastrointestinal effects
First pass metabolism