Flashcards in Week 3 Deck (47)
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1
What is pharmacokinetics?
What the body does to the drug: absorption, distribution, metabolism, excretion
2
Things that affect pharmacokinetics:
Age
Pregnancy
Hepatic/renal disease
Drug interactions
Ethnicity
Metabolism
GI surgery
Nutritional status
3
What is the fraction of unchanged drug teaching systemic circulation?
Bioavailability
4
Rate at which drug leaves site of administration and passes to systemic circulation. How drug enters the body.
Absorption
5
Factors affecting absorption:
Presence/absence of food in stomach
Blood flow to area
Formulation of drug
Size of molecule
Ionization
Cellular environment
Lipophilicity
Mechanism of absorption: passive diffusion or active transport
6
A drug that is more basic will be absorbed where:
A more basic environment such as small intestines
7
A drug that is more acidic will be absorbed:
In a more acidic environment like the stomach
8
This enhances renal clearance of drugs during toxicity.
Ion (drug) trapping
9
With an acidic drug overdose what would you give for ion trapping?
Sodium bicarbonate to make urine more alkaline and prevent reabsorption
10
For a basic drug overdose, what would you give?
Ammonium chloride to make more urine more acidic and prevent reabsorption
11
Most drugs are absorbed through the GI tract by:
Passive diffusion
12
How the drug will distribute through the body:
Volume of distribution
13
Volume of distribution depends on:
Solubility
Charge
Size
14
Larger Vd will concentrate where:
In tissues of the body- lipophilic drugs
15
Smaller Vd concentrates:
In the plasma- hydrophilic drugs
16
Properties affecting distribution:
Molecular size
Lipid solubility
Ph of environment
Ionization
17
A high degree of plasma protein binding can result in:
Restricted drug distribution
18
Active drugs being made less active to be excreted:
Metabolism/biotransformation
19
Metabolism occurs primarily here:
Liver
But also: intestines, skin, lungs, kidney, and brain
20
An inactive drug that becomes active with metabolism:
Prodrug
21
Phase I reactions occur through:
Oxidation (most common), reduction, and hydrolysis
22
What system does phase I metabolism occur:
Most often cytochrome 450 system
23
Goal of Phase I reactions:
Parent drug converted to a drug more easily excreted/water soluble.
24
With aging the livers capacity for metabolism through the P450 system is ___
Reduced by 30%
This drugs metabolized through this system reach higher levels and have prolonged half lives in the elderly
25
Explain CYP450 enzyme induction:
An inducing agent can increase the metabolism of another drug, resulting in the effect of the second drug being reduced. This can lead to therapeutic failure of the second drug.
26
Explain CYP450 enzyme inhibition:
An inhibiting drug can decrease the rate of metabolism of another drug, causing the second drugs level to rise and possibly result in harmful or reverse effect.
27
Phase II reactions are these types of reactions:
Glucurondiation
Acetylation
Sulfation
28
Phase II causes drugs to:
Conjugate with another substance to make drug more water soluble and easier to excrete.
29
Patients deficient in acetylation capacity (slow acetylators) may have:
Prolonged or toxic responses to normal doses of certain drugs bc of decreased rates of metabolism .
30
Factors affecting metabolism:
Age
Gender
Drug tolerance
Co-morbidities
Drug-drug interactions
Genetic differences
Diet and environment factors
31
Primary site of excretion is:
Kidney
32
Filtration works well for:
Hydrophilic, ionized compounds
33
Process of drugs being transferred from inside to outside the body.
Excretion
34
What types of drugs use biliary excretion:
Usually larger molecular weight drugs- erythromycin
35
Some ___ soluble drugs will get passively reabsorbed into circulation .
Lipid
36
Factors affecting renal excretion:
Renal function
Protein binding
Renal disease
37
If creating is elevated then creative clearance is
Decreased - drug will not be as easily excreted and there is an increased potential for toxicity
38
At a steady state, rate of clearance should be:
Equal to the amount of drug taken in
39
Time it takes the peak drug level in the bloodstream to drop by half after elimination from the body.
Half-life
40
High enough to maintain effect, low enough to prevent toxicity.
Steady state
41
Refers more broadly to the genome-wide (or an individuals entire DNA sequence) effects on drug therapy
Pharmacogenomics
42
Refers to a single or a few gene variations (called polymorphisms)
Pharmacogenetics
43
Poor metabolizers:
Slowly metabolize drug causing increase of drug in system
44
Poor metabolizers should have an increase or decrease in dosage?
Decrease
45
Ultra-rapid metabolizers:
Have an increased metabolism of drug causing therapeutic failure of drug
46
Ultra-rapid metabolizers need an increase or decrease in dosage?
Increase in dose to have effect
47
