Module 1 Part 4: Pharmacology Flashcards
(99 cards)
1
Q
what is the definition of a drug?
A
any chemical that affects the physiological processes of a living organism
2
Q
what is the definition of pharmacokinetics?
A
the study of the movement of drugs throughout the body
- also what happens to the drug on it’s journey
3
Q
what 4 processes does pharmacokinetics include?
A
- absorption
- distribution
- metabolism
- excretion
4
Q
what is the definition of absorption?
A
movement of drugs from the site of admission into the blood
5
Q
what is the definition of distribution?
A
drug movement from the blood to the interstitial space of tissues
6
Q
what is another word for metabolism?
A
biotransformation
7
Q
what is the definition of metabolism?
A
enzymatically mediated alteration of drug structure
8
Q
what is the definition of excretion?
A
movement of drugs and their metabolites out of the body
9
Q
what are the 3 ways to cross the cell membrane?
A
- passage through channels or pores
- passage with transport system
- direct penetration of the membrane itself
10
Q
what is P-Glycoprotein pump (PGP)?
A
multi-drug transporter
- transports drugs out of the cell
11
Q
Where is the PGP found?
A
in kidney, liver, placenta, intestines, capillaries of brain
12
Q
what does the rate of absorption determine?
A
how soon the effects will take place
13
Q
what does the amount of absorption determine?
A
how intense the effect will be
14
Q
what does large surface area mean in terms of absorption?
A
absorption happens faster
15
Q
where does absorption inc.?
A
where blood flow is HIGH
16
Q
what type of drugs can cross the cell membrane FASTER?
A
lipid soluble drugs
17
Q
what are the two common routes of administration?
A
- enteral
2. parenteral
18
Q
what is enteral?
A
via the GI tract
19
Q
what is parenteral?
A
outside the GI tract (injections)
20
Q
what is the faster route in terms of absorption?
A
intravenous (IV)
21
Q
what are the barriers to IV?
A
none; they are bypassed d/t being injected directly into blood stream
22
Q
what are the patterns of IV?
A
- instantaneous (enters directly)
2. complete (all goes into blood, none is lost during metabolism
23
Q
what are the advantages of IV? (4)
A
- rapid onset
- concise control
- permits use of large fluid volumes
- permits use of irritant gloves
24
Q
what are the disadvantages of IV? (6)
A
- high cost, difficult, inconvenient
- irreversible (can’t go back after injected)
- fluid overload
- infection
- embolism (BV blockage)
25
what are the barriers of IM? (1)
capillary wall (easy to pass)
26
what is the pattern of IM drugs?
rapid with water soluble drugs
27
what are the advantages of IM? (2)
- permits use of poorly soluble drugs
| - permits depot prepreration
28
what are the disadvantages of IM? (3)
- possible discomfort
- inconvenient
- potential for injury
29
which route has all the same characteristics as IM?
subcutaneous
30
what are the barriers of the oral route?
- lining of GI tract
| - capillary wall
31
why can you not crush slow/extended release drugs?
the beads that were meant to prolong the distribution in the body will crush and give a toxic dose
32
what is the pattern of oral admin.?
slow & variable
33
what are the advantages of the oral route? (5)
- easy
- inexpensive
- ideal for self-administration
- potentially reversible
- convenient
34
what are the disadvantages of the oral route?
- inactivation of same drugs
- possible nausea/vomiting
- pt must be conscious
35
what are the 3 major factors related to distribution?
1. blood flow to tissues
2. the ability of a drug to exit the vascular system
3. the ability of drugs to enter the cell
36
what can effect drug distribution?
tumors and abscesses
37
what is an abscess? what cannot reach here?
- a ball of puss
| - antibiotics cannot reach here
38
how do drugs exit?
through capillary walls
39
what is the blood-brain barrier (BBB)?
the unique anatomy of capillaries in the CNS
40
how does the BBB prevent drug passage?
tight junctions between cells that compose the walls of capillaries so tight that they block passage
41
what is the advantage of the BBB?
protects brain from injury of potentially toxic substances
42
what are the disadvantages of the BBB? (2)
- obstacle for certain CNS therapy
| - not developed at birth (dangerous for infants)
43
what is the placental drug transfer?
membranes separate maternal and fetal blood but DO NOT give absolute barrier to drugs
44
what can get into fetal blood?
lipid soluble, non-ionized compounds
45
what drugs cannot get into the fetal blood?
ionized, highly polar, or protein bound
46
how are the drugs returned back to the mother's circulation?
the PGP pump
47
what is protein binding?
drugs can form reversible bonds with proteins in the body
48
what is the most common protein drugs bind with?
plasma albumin
49
where does the most metabolism take place?
in the liver
50
what preforms metabolism in the liver?
the hepatic microsomal enzyme system (or P450 system)
51
what are the 6 consequences of the hepatic drug metabolizing enzymes?
1. accelerated renal excretion
2. inc. therapeutic action
3. activation of "pro drugs"
4. inc. toxicity
5. dec. toxicity
52
how does metabolism differ in children?
- in infants, it is limited
| - about 1 years old is when the liver can metabolize
53
what is a special consideration for older adults?
dosages may need to be dec. to avoid toxicity
54
what are inducers?
inc. rates of metabolism
55
what are inhibitors?
act on liver to dec. metabolism
56
what is the "first pass effect"?
rapid hepatic inactivation of certain oral drugs
57
what happens if the capacity of the liver is too high?
drugs can be inactivation
58
what happens if the pt is malnourished?
drug metabolism is compromised
59
what is the most common organ for excretion?
the kidneys
60
what does renal excretion limit?
the duration of action on drugs
61
how does renal failure affect the excretion of the drug?
may inc. the duration and action of drug
62
what are the 3 steps in renal excretion?
1. glomerular filtration
2. passive tubular reabsorption
3. active tubular secretion
63
what are the 3 factors that modify excretion?
1. pH dependant ionization
2. competition for active tubular transport
3. age
64
what are the 2 non-renal routes of excretion?
1. breast milk
| 2. feces - bile leaves body via feces
65
what is the minimum effect concentration?
(MEC) plasma during level below which therapeutic effects will not occur
66
what is the toxic concentration?
plasma level where toxic effects begins
67
what is the therapeutic range?
the range between MEC and toxic concentration
68
what is the objective of drug dosing?
to get it into therapeutic range
69
what is the def'n of drug half-life?
amount of time for the amount of drugs in the body to dec. by 50%
70
what does the half-life determine?
the dosing interval
71
what is the definition of the plateau?
when amount of drug elimination = dose administered
| average drug levels will remain constant
72
What is the peak concentration?
highest level conc.
73
what is the trough concentration?
lowest level conc.
74
what is the definition of pharmacodynamics?
study of biochemicals and physiologic effects of drugs on the body and the molecular mechanisms they produce
75
why are pharmacodynamics important for nurses?
- educates pt
- make prn decisions
- evaluate patients for beneficial and harmful drug effects
76
what is maximum efficiency?
the largest effect a drug can give
77
what is relative potency?
amount of drug needed to elicit the effect
78
what are drug receptors?
any functional macromolecule in a cell to which a drug binds to produce its effect
- (on-off switch)
79
what are the 4 drug receptor families?
1. cell membrane
2. ligand-gated ion channels
3. G protein-coupled systems
4. transcription factor
80
what are agonist drugs?
drugs that mimic the body's own regulatory molecules
| activate receptors
81
what are antagonist drugs?
block action of endogenous regulatory molecules
| prevents receptor activation
82
what is an example of an antagonist drug?
narcan
83
what is a partial agonist drug?
mimic the actions of endogenous regulatory molecules but they produce response of intermediate intensity
(prevent activation)
84
what is interpatient variability?
describes how the dose requirements vary from patient to patient
85
what is the definition of the average effective drug dose (ED50)?
the dose of drug that produces a therapeutic response in 50% of the population = standard dose
86
what is the definition of the therapeutic index?
safety of the drug
| - ratio of drug's ED to LD
87
what is LD50?
- lethal dose
| the amount of the drug that would kill 50% of the population
88
when do drug interactions take place?
when the patient is on two or more drugs
89
what are the 3 consequences of drug interactions? `
1. intensify effects
2. inc. therapeutic effect
3. inc. adverse effects
90
what are the 4 basic mechanisms of drug to drug interactions?
1. direct chemical or physical attraction
2. pharmacokinetic interaction
3. pharmacodynamic interaction
4. combined toxicity
91
what happens in drug-dug interactions with a narrow therapeutic range?
produces an inc. in drug levels that could lead to toxicity
92
what happens when you mix food with drug?
depends on the drug
| - could lead to either inc. or dec. absorption
93
what is the grapefruit juice effect?
inhibits the metabolism of certain drugs, therefore raises the drug levels
94
what happens with tyramine food?
oxidase inhibitor mixed with BP can raise to fatal level
95
what is the time frame of "administering of an empty stomach?
1 hour BEFORE meal or 2 hours AFTER
96
what is the placebo effect?
prep that is devoid of intrinsic pharmacologic activity
97
what does it mean if the patient has an effect on the placebo?
it is all psychological
98
what is the definition of bioavailability?
amount of active drug that reaches the systemic circulation from site of administration
99
what are the 3 ways that genes can play a factor in drugs?
- accelerate or slow metabolism
- inc. toxicity
- alter receptors
