Unit 3 Flashcards
Antagonist:
compounds which decrease the activity of the receptor or prevents an agonist from acting on a receptor
Partial agonist:
compound which increases or intensifies the activity of a receptor, which makes it an agonist but is less effective
Agonist:
compound which increases or intesifies the activity of a receptor (stimulator)
What is the difference between a competitive and noncompetitive antagonist?
A competitive antagonist binds to the same site on a receptor as an agonist while a noncompetitive antagonist binds to a different part of a receptor but still prevents normal agonist action.
What is the difference between a structurally specific and non structurally specific drug?
Structurally specific drugs; Work by receptor theory
Structurally non-specific drugs: Work by simple physical or chemical action
What are the factors that influence the rate of drug passage through a membrane?
- The size and shape of molecule
- Lipid solubility
- Degree ionization
- pH of surrounding medium
Understand ionization and how it influences drug movement (Influenced by pH)
Acids (ex barbituates)
- Less ionized at low environment pH
- More ionized at high environmental pH
Bases (ex: morphine/ quinine)
- Less ionized at high environmental pH
- More ionized at low environmental pH
What factors affect drug absorption?
- Acid in unlike base environment is more ionized
- Bases in like base environment is less ionized
- Base in unlike acid environment is more ionzed
- IN SIMILAR ENVIRONMENTS ARE LESS IONIZED
- IN OPPOSITE ENVIRONMENTS DRUGS ARE MORE IONZED
- UNIONIZED DRUGS MOVE THROUGH MEMBRANES MORE RAPIDLY
How does the presence of food (or timing of drug dosage around meals) alter drug absorption?
Food can affect the rate of absorption of the drug and the extent of absorption
In terms of drug distribution, how does the blood brain barrier differ from the placential barrier?
BBB-It is harder for drugs to cross the blood brain barrier since the pores are smaller and are plugged with glial cells
Placentia-There is basically no barrier, Some proteins and viruses cross
What is the effect of plasma protein binding on drug distribution?
It sequesters drugs in a non-diffusible form and slows the transfer out of the vascular department
Where are drugs metabolized?
Usually the liver (also blood enzymes, intestinal mucosa)
What is the significance of induction and inhibition of the CYTP450 system?
- Induction increases the rate of metabolism
- Inhibition reduces the rate of metabolism
Review the individual patient differences that may affect absoprtion, distribution, metabolism
And excretion of drugs
And excretion of drugs
A) age (enzymes, blood brain barrier)
B) weight (sometimes use surface area)
C) Size, Body composition, pregnancy, nursing
What is the difference between a drugs idiosyncracy and a drug allergy?
- Idiosyncracy is an abnormal non-allergic response
- Drug allergy has to do with responses to histamine
