Orientation to Pharmacology Flashcards
1
Q
What is pharmacokinetics ?
A
The body’s effect on drugs - involves drug absorption, drug distribution, drug metabolism and drug excretion
2
Q
What is pharmacodynamics?
A
This is the impact of drugs on the body
3
Q
What are the three properties of an ideal drug?
A
Effectiveness, Safety, and Selectivity
4
Q
Is there such a thing as an ideal drug?
A
No- there is no ideal drug that does not cause any side effects.
5
Q
What is the most important property a drug can have?
A
Effectiveness - the drug elicits the response for which it is given
6
Q
What is the therapeutic objective ?
A
The objective of drug therapy is to provide maximum benefit with minimal harm
7
Q
Drug _______ , ________, and ____________________ are important determinants of drug responses.
A
dosage; route; timing of administration
8
Q
Pharmacokinetic processes determine how much of an administration dose gets to its ______________
A
sites of action
4 major pharmacokinetic processes-
ADME
9
Q
Once a drug has reached its site of action, pharmacodynamic processes determine _________ and ________________ of the ___________.
A
nature; intensity; response
10
Q
In most cases the initial step leading to a response is the ______________ of a drug to its _____________
A
binding; receptor. This is followed by a sequence of events that ultimately leads to a response
11
Q
Characteristics unique to each ______________ can influence the _____________ and ____________________ processes and by doing so can help determine the ________________ to a drug
A
patient; pharmacokinetic; pharmacodynamic; patients response
12
Q
Sources of individual variation when it comes to the patients response to a drug
A
Drug interactions, age, gender, weight, pathologic variables especially the diminished function of the kidneys and liver, the major organs of drug elimination and genetic variables
13
Q
Genetic factors can alter the _____________ of drugs and can predispose the patient to unique _________ dr
A
metabolism; drug reactions
14
Q
No two patients will response identically to the same drug regimen. True or false.
A
true - everyone is different and genetically unique
15
Q
To achieve the ___________, we must tailor drug therapy to the _________________.
A
therapeutic objective; individual
16
Q
Our ultimate concern when administering a drug is _________________
A
the intensity of the response
17
Q
The intensity of the response is determined by the _______________ of a drug at its ______________-
A
concentration; sites of action
18
Q
What are factors that determine the intensity of drug responses ?
A
Administration
Pharmacokinetics
Pharmacodynamics
Sources of Individual Variation
19
Q
Important events will take place after the ________________ is delivered and these must be __________ to.
A
Medication; responded
Remember the MLB pitcher analogy that likened the nurses response to medication administration and response to a pitcher throwing a pitch and anticipating what would happen next
20
Q
What is the role of the FDA in drug regulation and safety?
A
The FDA regulates the pharmaceutical industry by approving drugs for marketing and use. Its aim is to make drugs safer, more effective and more affordable. It advances public health and aids public in getting accurate science based information.
It also provides rigorous oversight of drug safety after a drug has been approved.
The FDA regulates: Foods Dietary Supplements Drugs Prescription and Non-prescription Biologics Vaccines Blood and Blood products Medical Devices Tongue depressors Bed pans Heart Pace makers Electronic: Products that give off radiation Xray equipment Cosmetics Veterinary Products Tobacco Products
21
Q
What is the most reliable way to objectively assess drug therapies ?
A
Randomized Controlled Trials
22
Q
What are OTC agents ?
What is CAM ?
A
Over the Counter agents such as vitamins and supplements
they are the most common form of Complementary and Alternative Medicine
23
Q
Commonly used dietary supplements include
A
Cranberry Juice Echinacea Garlic Ginger Root Ginkgo Biloba Green Tea Probiotics St. John’s Wort Valerian Root
24
Q
FDA regulations for dietary supplements
A
dietary supplements do not have to be approved by the FDA
Manufacturer must notify the FDA of efficacy claims
Has authority to intervene if supplement becomes harmful
Only after it has been released for marketing
25
What does pharmacokinetics determine ?
How much of an administered drug gets to its sites of action
26
Drug absorption factors
Rate of Dissolution- before a drug can be absorbed, it must first be dissolved; drugs with rapid dissolution have a faster onset than drugs with a slow dissolution
Surface Area: major determinant of rate of absorption; the larger the surface area, the faster the absorption
Blood Flow:drugs are absorbed most rapidly from sites where blood flow is high
Lipid Solubility: highly soluble drugs are absorbed more rapidly than drugs whose lipid solubility is low; lipid-soluble drugs can readily cross membranes, whereas low lipid-soluble drugs cannot
pH Partitioning
27
What are the different absorption patterns for IV, IM, SQ and Oral routes ?
IV is instantaneous absorption
IM and SQ are both relatively more rapid in being absorbed
Oral absorption is slowest
28
What is the distribution of the drug determined by?
Blood flow to tissues
Ability to exit the vascular system
Ability to enter the cell
29
What is an abscess ?
A puss filled pocket with no internal blood flow- antibiotics would not reach the bacteria there and would not prove effective unless the abscess is drained
30
Tumors have _________________ ______________ supply, which would affect drug therapy.
limited blood
31
Factors affecting the passage of the drug through the cell membrane
Lipid solubility
| presence of a transport system
32
What is metabolism defined as for drugs ?
| Where does most drug metabolism take place ?
The enzymatic alteration of a drug structure
Most drug metabolism takes place in the liver
33
To directly penetrate membranes ..... a drug must be
lipid soluble
34
What organ accounts for the majority of drug excretion ?
The kidneys
Glomerular Filtration
Passive Tubule Reabsorption
Active Tubular Secretion
Drugs are removed from the body through urine (renal excretion) and sweat, bile, saliva, breast milk and expired air (all non renal excretion methods)
Decreased kidney function = delayed excretion
35
Compare effect of healthy kidneys on drug's duration of action with that of failing kidneys
Healthy kidneys will limit the duration of action of many drugs while failing kidneys result in an increase in the duration and intensity of drug responses
36
Drugs must cross cell membranes by what 3 ways ?
1. Through Channels or Pores
2. Aid of a Transport System
3. Direct Penetration of a Membrane
37
Very few _________ cross membranes via ________________ because of how small they are; only the smallest of compounds pass through these channels; some of these compounds include: ________________
drugs; channels/pores; SODIUM and POTASSIUM
38
What do transport systems of cells do ?
Move drugs from one side of the cell membrane to the other
39
Will transport systems carry any drug ?
No they are selective; it is dependent on the drugs structure
40
What is one of the most important transporters of the cell?
P Glycoprotein
41
What is P Glycoprotein ?
a multi-drug transporter protein; It carries many drugs out of cells and can be found in many cells in the LIVER, KIDNEY, PLACENTA, INTESTINES, CAPILLARIES OF THE BRAIN
42
Discuss the action of P Glycoprotein within different organs in the body
In the liver P-glycoprotein transports drugs into bile for excretion
In the kidneys P-glycoprotein pumps drugs into the urine for excretion
In the placenta P-glycoprotein transports drugs back into maternal blood to reduce fetal drug exposure
In the intestines P-glycoprotein transports blood into the intestinal lumen reducing drug absorption into the blood
In the brain capillaries, P-glycoprotein pumps drugs into the blood thereby limiting access to the brain
43
Parenteral Routes of Administration
Subcutaneous
Intramuscular
Intravenous
44
Other routes of Administration
```
Oral
Aural
Ocular
Inhaled
Topical
Transdermal
Suppositories (Rectal or Vaginal)
```
45
Absorption pattern of IM route
Rapid-w/ water soluble drugs
Slow-w/ poorly soluble drugs
46
Absorption pattern of oral route
Slow and Variable
47
Distribution is defined as ................
the movement of drugs throughout the body -
drugs move from the blood into the tissues and cells
48
Abcesses and tumors affect ___________________ because there is _________________
drug distribution; low blood flow
49
Blood Flow of Tumors
Solid tumors have limited blood supply, central blood flow is markedly decreased, though the outer region has high blood flow; Achievement of high drug levels deep inside the tumor is not achieved making them highly resistant to drug therapy
50
What is necessary in order for drugs to undergo metabolism and excretion ?
They must exit the vascular system
51
Drugs in the vascular system leave the blood at
Capillary beds
Through the blood-brain barrier
Placental drug transfer
Protein binding
52
How can drugs leave typical capillary beds ?
By passing between the spaces between capillary cells that make up the vessel, rather than pass through them.
53
Some drugs must enter cells to reach their __________________
sites of action
54
All drugs must enter cells in order to undergo __________________ & ________________.
metabolism & excretion
55
Factors that determine the ability of the drug to enter the cell
Lipid Solubility
Transport Proteins
Both
56
How is metabolism defined ?
The enzymatic alteration of drug structure
57
Most drug metabolism takes place where?
In the liver
58
What is the most important consequence of drug metabolism ?
Renal drug excretion
59
Are the kidneys able to excrete drugs that are highly lipid soluble ?
No, they are not
60
How does metabolism accelerate renal drug excretion?
By changing highly lipid soluble drugs into more hydrophilic, water soluble substances that are more easily and rapidly excreted by the kidneys.
61
Drug metabolism can convert pharmacologically active compounds to _________________-
inactive forms
62
Metabolism can increased the ________________ of some drugs.
Effectiveness
the conversion of codeine to morphine - morphine has much greater analgesic effects
63
What does activation of prodrugs means ?
A inactive form of a drug is administered which then undergoes metabolic changes to become an active form
64
By converting drugs into inactive forms, metabolism can decrease ________________
toxicity
65
Metabolism can increase ________________ by converting relatively safe compounds into forms that are ________________-
the potential for harm; toxic
66
Special Considerations in Drug Metabolism: Age
Infants are especially at an increased risk for drug sensitivity because liver's drug metabolizing capabilities are not fully developed until 1 year after birth.
Older adults also are at increased risk of toxicity because their ability to metabolize drugs is commonly decreased.
67
Drugs may be P450 __________, P450 enzyme ____________ and P450 enzyme ___________.
substrates; inducers; inhibitors
68
What are drugs that are metabolized by P450 enzymes called ?
Substrates
69
True or false- a drug can be both an inducer and a substrate......
True..... If the drug is both an inducer and a substrate, by stimulating the liver to produce more drug metabolizing enzymes, the drug can increase the rate of its own metabolism, thereby necessitating an increase in its dosage to maintain therapeutic effects.
70
True or false .... the induction of drug metabolizing enzymes can decrease the metabolism of other substrates used concurrently, allowing for no changes in their dosages to keep levels steady.
False..... the induction of drug metabolizing enzymes can accelerate the metabolism of other substrates used concurrently, necessitating an increase in their dosages
71
What are inhibitors as it relates to metabolism ?
Drugs that act on the liver to decrease rates of drug metabolism.
72
What is one therapeutic effect of inhibitor drugs on metabolism ?
Because they slow the rate of drug metabolism, it is possible that other drugs used concurrently can reach toxic levels or have adverse effects.
The active accumulation of a drug due to the slower metabolism must be carefully monitored.
73
The first pass effect refers to the
rapid hepatic enzyme inactivation of certain oral drugs - as a result, a dosage may have no therapeutic effect. In order to bypass this, drugs that are rapidly inactivated by hepatic enzymes can be administered through another route or their dosage is increased to counteract the first pass effect.
74
How can nutritional status affect the rates of drug metabolism?
Certain cofactors are needed by hepatic drug metabolizing enzymes in order to function. A malnourished patient may be deficient in some of these cofactors, thereby compromising drug metabolism.
75
How can competition between drugs affect their metabolism?
Two drugs that are metabolized by the same metabolic pathway may be competing with each other for metabolism. Since there are winners and losers, one drug may be metabolized more slowly than the other.
Therefore, drug levels must be monitored for toxicity because the one that has a decreased rate of metabolism may accumulate to dangerous levels.
76
Drugs can be excreted through the
urine, bile, sweat, breast milk, saliva and expired air
77
Urinary excretion is the net result of what 3 processes .............
glomerular filtration
passive tubular reabsorption
active tubular secretion
78
When two drugs are taken together what can happen?
one may alter the absorption, distribution, metabolism or excretion of the other
Altered Absorption: May be enhanced or reduced
Altered Distribution: Competition for protein binding and alteration of extracellular pH
Altered Metabolism: Increase or decrease metabolism of other drug
Altered Excretion: One drug can alter the renal excretion of another
79
Why do clinicians monitor plasma drug levels in efforts to regulate drug responses ?
It has been shown that there is a direct correlation between therapeutic and toxic responses and plasma drug levels.
More often than not, it is a practical impossibility to measure drug concentrations at sites of action
80
Which two plasma drug levels are of special importance?
The minimum effective concentration and the toxic concentration
81
What is the MEC?
The minimum effective concentration is defined as the plasma drug level below which therapeutic effects will not occur.
Example: any dose of warfarin below ______ will have no therapeutic effect
82
How is toxic concentration defined ?
When drug levels within the plasma climb too high....
| levels are high enough that toxic effects begin
83
What is the therapeutic range ?
The plasma drug levels falling between the toxic concentration and the MEC
84
Which drug is safer: one with a wider therapeutic range or one with a narrower therapeutic range?
The drug with the wider therapeutic range
85
A drug with a narrow therapeutic range must be administered .......................
carefully. There is little room for error between the MEC and the toxic concentration
86
What is the objective of drug dosing ?
To administer drug doses within the therapeutic range
87
Patients taking drugs with a _________________ therapeutic range are the most likely to require intervention for drug-related concentrations.
Narrow
88
Drug responses cannot occur until ....................
The drug has reached the MEC within the plasma
89
Drugs with a short half life leave the body ______________.
| Drugs with a long half life leave the body ______________.
quickly; slowly
90
Morphine has a half life of 3 hours - how many mg of morphine will be present in the body after 3 hours ? After another 3 hours ?
25 mg after 3 hours
An additional 3 hours would result in 12.5 mg
91
What determines the dosing interval (how much time separates each dose)?
The half life of a drug
92
What is the dose response relationship ?
The relationship between the dose of the drug and the intensity of the effect it will produce...
93
What does it mean to say the the dose-response relationship is the "graded" ?
The greater the dose amount, the more intense the effect will be.
Because the dose-response relationship is graded, we can adjust dosage levels accordingly to achieve the desired therapeutic effect.
94
What is maximal efficacy and relative potency ?
The largest effect that a drug can produce
| and the amount of drug that we must give to elicit that effect.
95
Potency refers to the fact of a drug ..................
producing its effect at low doses.
96
The dose response relationship determines .............
the minimum amount of drug we can use
the maximum response a drug can elicit
How much we need to increase the dosage in order to produce the desired increase in response.
97
What are receptors as it pertains to
| drug interactions ?
Special chemicals in the body that most drugs interact with to produce effects
98
What are the four primary receptor families ?
4 Primary Receptor Families
1. Cell Membrane-Embedded Enzymes
2. Ligand-Gate Ion Channels
3. G Protien-Coupled Receptor Systems
4. Transcriptions
99
Difference between agonist and antagonist
Mimic the body’s own regulatory molecules
Activate receptors
Affinity allows the agonist to bind to receptors
Intrinsic activity allows the bound agonist to activate receptor function
Antagonists
Block actions of regulators
Produce their effects by preventing receptor activation
100
Do agonists or antagonists treat overdoses?
Antagonists
101
Opioid overdose produces ________________.
| what should one do?
respiratory depression.
| Block the receptor sites by giving an opioid antagonist (Narcan) and engage in competitive antagonism
102
True or false .... some drugs do not act through receptors
True .... some drugs act through simple physical or chemical interactions with other small molecules
103
Examples of "receptorless" drugs
Antacids, antiseptics, saline laxatives and chelating agents
104
Receptors are dynamic components of ________________. What can happen when there is continuous stimulation of receptors by agonists or continuous exposure to antagonists.
The number of receptors on the cell surface can change as can their sensitivity to agonist molecules.
When the receptors of a cell are continually exposed
to an agonist, the cell usually becomes less responsive..... think of insulin resistance
Continuous exposure to antagonists has the opposite effect, causing the cell to become hypersensitive.
105
The nurse who appreciates the reality of ______________ _____________ will be better prepared to anticipate, evaluate and respond appropriately to each patients ______________
interpatient variability; therapeutic needs
106
What does a high therapeutic index indicate ?
That a drug is relatively safe
107
What does a low therapeutic index indicate ?
That a drug is relatively unsafe
