pharmacology intro Flashcards
What does rate of filtration depend on
Extend of plasma protein binding
How can the solubility of a drug be described?
Limited
How do drugs leave the circulation
filtration through capillaries
What does amphipathic mean?
Having both hydophillic and hydrophobic parts
What are mostly amohipathic
Proteins
What are lipophilic compounds attracted to?
What happens when they attract?
They are attracted to lipophiloc grounds and become loosely bound to protein molecule
How long do drugs bind for
They bind temporarily
What is there an equalibrium between
Bound and free drugs
What do drugs mostly bind to
Mostly to albumin
Then: globulins, glycoproteins and lipoproteins
Do proteins leave the bloodstream
No
What drugs pass into other compartments and how?
Non-bound drugs bind to cellular receptors, pass across the membrane into other compartments
What drugs can be distributed, metabolised and excreted ?
Only non-bound drugs
What happens if a free drug leaves the bloodstream
More free drug will be released from the protein to maintain the equilibrium
What prolongs the time a drug is in the plasma?
Strong protein binding
How many drugs compete for binding sites? Why is this important
Give an example
2 - this is important when giving more than one drug - eg warfarin and asprin
What are the body fluid compartments?
Plasma, extracellular fluid, intercellular fluid, fat
What does distribution between compartments depend on?
Permeability across barriers
PH of compartments
Binding capacity
Fat solubility of drug
What does the blood brain barrier consist of
Continuous layer of endothelial cells- joined by tight junctions
How do drugs pass into the brain
The brain is inaccessible to many drugs.
Hugh lipid solubility is needed
What happens when there is inflammation in the brain
Disrupted integrity - can use penicillin in bacterial meningitis
Where is the blood brain barrier weak?
It is leaky in zones CTZ
What barriers are there in the body
Placental barrier
Blood brain barrier
How is the placenta barrier
Not very efficient.
Most drugs cross
