Quiz 1 Flashcards
1
Q
Pharmacotherapeutics
A
the use of a drug to diagnose, prevent or treat disease or to prevent pregnancy.
2
Q
Effectiveness
A
does it cause the response for which it was given
3
Q
Safety
A
there is no such thing as a safe drug
4
Q
Selectivity
A
Causes only the response for which it is given
there is no such thing as a selective drug
5
Q
Reversible action
A
do drugs actions subside after a certain amount of time?
6
Q
Predictability
A
How does the pt. respond
7
Q
Components of a drug
A
- Prescribed Dose
- Administered Dose
- Concentration at site of action
- Intensity of response
8
Q
Sources of Individual Variation
A
- Physiologic variables
- Pathologic variables
- Genetic variables
- Drug interactions
9
Q
side effects
A
expected
10
Q
Adverse effects
A
unexpected/uncommon (HGD- he gonna die)
11
Q
Pharmacokinetics
A
(study of drug movement through the body)
Absorption
Distribution
Metabolism
Excretion
12
Q
Passage of drugs across membranes
A
- Channels or pores
- Transport systems
- Direct membrane Penetration
13
Q
Absorption of a drug
A
Movement of a drug from site of administration into the blood
1.Rate of absorption
2.Amount of absorption
3. Factors affecting absorption
o Rate of dissolution
o Surface area
o Blood flow
o Lipid solubility
o pH partitioning
14
Q
Parenteral Routes of Administration
A
IV, IM, SubQ
15
Q
Enteral
A
Use of GI Tract
- oral
- suppository
16
Q
Advantages/barriers to IV
A
Fastest route of absorption- no barriers. (faster the onset, faster it wears off)
Advantages: rapid onset, control of level of drug, ability to administer large volumes of fluid
Disadvantages: expensive, inconvenient, cannot take it back, infection, fluid overload, embolism
17
Q
Advantages/barriers to IM
A
IM- no barriers, easily passes through spaces of capillary wall
- Patterns of absorption
- Rapid or slow (depo)
- Water solubility of the drug
- Blood flow to the site of injection
Advantages
- Good for meds with poor water solubility
- Used for administration of depo preparations
Disadvantages
-Discomfort, inconvenient, can be painful, infection, nerve damage
18
Q
Advantages/barriers to SubQ
A
Barriers to absorption
-None easily passes through spaces of capillary wall
Patterns of absorption
- Rapid or slow
- Water solubility of the drug
- Blood flow to the site of injection
Advantages
- Good for meds with poor water solubility
- Used for administration of depot preparations
Disadvantages
-Discomfort, inconvenient, can be painful, infection, nerve damage
19
Q
Advantages/barriers to Oral
A
Advantages
-Easy, convenient, safe
Disadvantages
- Variability of absorption
- Requires patient cooperation
** it is not SAFE to give extended release drugs via NG tubes**
20
Q
Oral Preparations
A
Tablets
enteric-coated, sustained/extended release
21
Q
Chemical Equivalence
A
generic V brand name
22
Q
bioavailability
A
rate at which a drug is absorbed into the system; timeframe
the fraction of the administered dose that reaches circulation
IV -100%
23
Q
Additional Routes of Administration
A
Topical
transdermal: pain patch, birth control patch, topical creams
Sublingual- under the tongue
Inhalation: inhalers/nebulizers
suppository-vaginal/anal
Direct injection into the site of action
( ex. cortisone shots)
24
Q
Distribution
A
The movement of drugs throughout the body
3 main factors
1. ability to exit the vascular system
- capillary beds
-blood brain barrier
( tight junctions, not fully developed in infants)
- placental drug transfer - protein binding
- ability to enter the cells
- some drugs must enter cells to reach their sites of action and most must enter to undergo metabolism or excretion ( lipid solubility; transport system)
3.blood flow to tissues
- 2 pathologic conditions in which low regional blood flow can affect drug therapy
( 1. abcess, 2. tumors)
25
Metabolism
The enzymatic alteration of drug structure
26
Main site for drug metabolism
LIVER
Cytochrome P450 System
27
Therapeutic Consequences of drug Metabolism
```
o Accelerated renal excretion
o Drug inactivation
o Increased therapeutic action
o Activation of prodrugs (changes its chemical body once the metabolism (enzymes like cytochrome) breaks its down)
o Increased or decreased toxicity
```
special considerations:
weight
age
28
First Pass Effect
Rapid inactivation of some oral drugs as they pass through the liver after being absorbed
( parenteral administration will bypass this effect)
29
Drugs and Nutritional Status
Adequate nutritional status provides the required cofactors for the hepatic drug metabolizing enzymes to function
30
Competition between drugs
o Two or more drugs that use the same metabolic pathway may cause a decrease in metabolism of one or more
31
EXCRETION
The removal of drugs from the body
32
renal drug excrection
1. Glomerular Filtration
2. Passive Tubular Reabsorption
3. Active Tubular Secretion
33
Nephrotoxic drugs
Can injure the kidneys
34
Factors that modify renal drug excretion
- pH- dependent Ionization
| - competition for active tubular transport
35
Non-renal routes of excretion
breast milk
biles
lungs
sweat/saliva
36
Plasma drug levels
Plasma drug levels are highly predictive of therapeutic and toxic responses
37
minimum effective concentration (MEC)
The minimum plasma drug level at which therapeutic effects will occur (lowest dose to see relief)
38
Toxic Concentration
The level at which toxic effects occur
39
Therapeutic Range
- Falls between the MEC and toxic concentration
| - Enough drug is present to produce a therapeutic response
40
Narrow Therapeutic Range
-Narrow therapeutic range (Drugs we screen labs for, because the range is so narrow)
41
Drug Half Life
¬ The time required for the amount of drug in the body to be decreased by half
42
Plateau
~Ideal to achieve~
- When a steady level of drug has been achieved
- When the amount of drug eliminated between doses equals the dose administered
43
How do you reduce fluctuations in drug levels
- administer continuous infusion
- administer a depot preparation
0reduce the size of a dose and the dosing intervals
44
Peak
The highest level of drug
45
Trough
The lowest level of drug
46
Loading dose
used when plateau must be achieved quickly
47
Maintenance dose
smaller doses used once plateau is achieved
short dose, over longer periods of time to keep pt in therapeutic range.
48
PHARMACODYNAMICS
The relationship between the size of an administered dose and the intensity of the response produced
o The minimum amount of drug needed to elicit a response
o The maximum response a drug can elicit
o How much to increase the dosage to increase the response
49
Maximal efficacy
largest effect that a drug can produce
50
Potency
o Amount of drug given to elicit an effect
o A potent drug produces its effects at low doses
***Two drugs can be equally effective but have different potency******
51
Receptors
o Chemical sites in the body that drugs interact with to produce effects – make selective drug action happen
****Drugs either mimic OR block the action of the body’s own regulatory molecules; do NOT give cells new functions
52
affinity
Affinity (ability to bind to receptor)
High affinity drugs have a strong attraction for receptor sites
o Drugs with high affinity are very potent
o Drugs with low affinity need to be present in high concentrations to elicit a response
53
Intrinsic activity
(bond that MIMICS receptor)
- Ability of a drug to activate a receptor upon binding
- Drugs with high intrinsic activity have high maximal efficacy; produce an intense response
54
agonist
(MIMICS what the body already does)
¬ Activate receptors; have high affinity and intrinsic activity
¬ Mimic action of endogenous regulators
55
Antagonist
(BLOCKS what the body normally does)
¬ Prevent receptor activity
o Have high affinity but no intrinsic activity
o Bind to receptors but do not cause receptor activation
o Block actions of endogenous regulatory molecules or drugs
♣ Response to an antagonist is determined by how much agonist is present
56
Desensitization
¬ (Refractoriness) results from continuous exposure of cell receptors to an agonist
o The cell is less responsive
(May need to increase the dose, you can become desensitized to the benefits from the drug, but not desensitized to the adverse effects)
57
Hypersensitivity
¬ results from continuous exposure of cell receptors to antagonist
o The cell is hypersensitive
(Profound response due to an influx of receptor sites (hypersensitivity) do to continuous exposure)
58
Average effective dose (ED50)
o Dose required to produce a defined therapeutic response in 50% on the population.
59
Therapeutic Index (ED50:LD50)
o Ratio between average effective dose and average lethal dose
¬ Wide therapeutic index is relatively safe
¬ Narrow therapeutic index is relatively unsafe
60
Drug-drug Interactions
Three ways drugs interact
1. One drug intensifies the effects of the other
2. One drug reduces the effects of the other
3. The combination produces a new response not seen with either drug alone
61
Intensification Effects
AKA: (Potentiative) Effects
o Increased therapeutic effects
o Increased adverse effects
62
Reduction effects
AKA: (Inhibitory) Effects
o Reduced therapeutic effects
o Reduced adverse effects
63
Mechanism of Drug-drug Interactions
Pharmacodynamic Interactions
o Drugs act at the same site
o Drugs act at separate sites
64
Combined toxity
The more drugs a patient receives the greater the chance there will be an interaction.
65
Drug-food interactions
- Food and drugs may interact to alter the effect of pharmacotherapy.
- Decreased absorption
- Increased absorption
- Risk for toxicity may increase with drug food interactions
- Drug action may be decreased
66
Timing in respect to meals
Administer on an empty stomach or with food
-empty = 1-2 hrs after eating
with food= with or shortly after
67
Grapefruit effect
grapefruit inhibits an isoenzyme responsible for intestinal metabolism of multiple drugs
- the inhibitory effect is dependent on the mount f juice consumed and can persist up to 3 days
Increases amount of drug available for absorption which increases the blood level of drugs
*patient teaching point*
68
Drug-herb interactions
Drug interactions may also result from herbal supplements interacting with drugs
- they can impact therapeutic outcome of prescribed agents
- increased toxicity
- reduced therapeutic outcomes
69
Adverse drug reactions
Adverse effect of drug therapy (NOT EXPECTED)
| o An effect other than the desired therapeutic effect that may occur during drug therapy.
70
side effect
```
Side effect (often MINOR, EXPECTED)
o Usually refers to a minor effect, such as nausea, nearly unavoidable secondary drug effect produced at therapeutic dosing.
```
71
Toxicity
Severe
-caused by excessive dosign
72
Allergic reactions
immune response
- must have had a prior sensitization
- Allergic reactions are not determined by the size of the dose but by the degree of sensitization
73
Anaphylaxis
¬ Anaphylaxis is the most serious of allergic reactions…it is a medical emergency
o A systemic reaction
♣ contraction of smooth muscles…airway closes
♣ increased vascular permeability…swelling
o So it looks like this…
♣ dyspnea, bronchospasm, laryngeal edema, cardiac dysrhythmias, and occasionally seizures.
74
Idiosyncratic drug response
o Unusual, abnormal or peculiar response to a drug
o Idiosyncratic responses are thought to occur because of genetic enzymatic deficiencies that alter the drug’s metabolism
75
Paradoxical response
(could happen once or could happen again)
| o Opposite of an intended drug response
76
Iatrogenic Disease
(drugs and their side effects start to mimic other disease processes)
o A disease that occurs as a result of medical care or treatment
o Can be the result of drugs
77
Drug Toxicity
Toxicity results when the dosage of drug or drugs exceeds the amount the body can eliminate through metabolism and excretion
78
Physical dependence
o A state in which the body has adapted to prolonged drug exposure in such a way that abstinence syndrome will result if drug use is discontinued
79
Abstinence Syndrome
Withdraw-
varies depending on drug
* Patient teaching point*
80
Carcinogenic effect
o Ability of certain medications and environmental chemicals to cause cancer
81
Teratogenic Effect
Drug induced birth defects
82
Neuro Toxity
The brain is sensitive to small amounts of toxic substances
¬ Neurotoxicity can occur after exposure to drugs and other chemicals and gases.
¬ Signs and symptoms of neurotoxicity
o changes in level of consciousness (drowsiness, restlessness)
o auditory and visual disturbances, nystagmus
o tonic-clonic (grand mal) seizures
83
Hepatotoxicity
Liver is the primary site of drug metabolism
-The liver is highly susceptible to toxicants due to direct exposure to ingested drugs and other toxicants
```
S/S of hepatotoxicity
o Hepatitis
o Jaundice
o Elevated liver enzymes [laboratory values]
o Fatty infiltration of the liver.
```
84
Nephrotoxicity
High susceptibility due to high vascularity
-Chemically induced kidney damage is typically manifested as acute tubular necrosis
-Laboratory Values to assess
o Blood urea nitrogen (BUN)
o Creatinine
o Creatinine clearance
85
Immunotoxicity
- A wide variety of drugs can affect the immune system.
- Some may cause immunosuppression (decrease ability to fight infection),
- whereas others may directly destroy immune system components (i.e.leukocytes).
86
Cardiotoxicity
- Irregularities in cardiac rhythms and conduction and possibly heart damage may result from an adverse effect known as cardiotoxicity.
- Cause unknown
- Characteristics of cardiotoxicity include transient cardiac arrhythmias and depression of myocardial function
- Prolonged QT interval
87
Ototoxicity
-Many drugs can produce ototoxicity, which affects the eighth cranial nerve and result is inner ear or auditory nerve damage.
- Structures of the inner ear that may be affected include the cochlea, vestibule and semicircular canals.
- Ototoxicity may or may not be reversible.
88
Variations in drug reponse
#1 Pathophysiology
- renal disease affects secretions
-liver disease affects metabolism
MUST Adjust dosage for both
```
#2 Body surface area is more precise than body weight
o Percentage of body fat can change drug distribution
```
#3 Extreme of age are more sensitive ( babies/elderly)
```
#4 Gender related differences
(most research previously performed on men )
```
- acid base imbalances
- altered electrolytes ( ie. digoxin toxicity)
89
Tolerance
-Decreased responsiveness to a drug as a result of repeated drug administration
-Patients who are tolerant to a drug require higher doses to produce the same effects that were achievable with lower doses before tolerance had developed
(increase dose/concentration, increase frequency)
90
Metabolic tolerance
-Related to accelerated drug metabolism
-Certain drugs can induce synthesis of drug metabolizing enzymes causing increased metabolism of other drugs
(drug-drug interactions)
91
Tachyphylaxis
-A form of tolerance where the reduction in drug responsiveness is brought on by repeating dosing over a short time (within hours) instead of days to weeks
(loading dose, giving a large amount in a short period of time)
92
Placebo Effect
-Caused by psychological factors not chemical properties of the drug (illegal)
93
Variability in Absorption
BIOAVALABILITY
o The amount of active drug that reaches the systemic circulation from its site of administration
o Different forms of the same drug can vary in bioavailability
o Primarily occur in oral preparations
o Highest concern in drugs with narrow therapeutic range
94
Genetics
play a role in drug metabolism etc. etc. etc.
95
Diet
-Malnutrition
o Lower amounts of plasma proteins (albumin) causing levels of free drug to rise – more intense effects, possible toxicity
o Decreased oxidative metabolism & decreased glomerular filtration rate
- Intake of Vitamins
- Urinary pH
- Timing of meals
96
Drug therapy during pregnancy
¬ Err on the side of caution, any drug taken during pregnancy will reach the fetus
¬ Physiologic Changes during pregnancy can alter pharmacokinetics of drugs
o Renal
o Liver
o Gastrointestinal
¬ Placental drug transfer
97
Pregnancy Catagories
¥ Based on research for risks posed to the fetus (teratogenic effects)
¥ Category A and B (remote risk) –lowest chance of adverse effect
¥ Category D (proven risk)
¥ Category X (proven risk)
98
Geriatric population
```
¬ Challenges of drug therapy in older adults
o Pharmacokinetic changes
o Multiple and severe illnesses
o Multidrug therapy
o Poor adherence
¬ Pharmacokinetic changes in older adults
o Absorption
o Distribution
♣ Increased percent of body fat
♣ Decreased percent of lean body mass
♣ Decreased total body water
♣ Reduced concentration of serum albumin
¬ Metabolism
¬ Excretion
o Creatinine clearance rather than serum creatinine is a better indicator in older adults of renal function
```
¬ Monitoring and preventing adverse drug reactions and drug-drug interactions
¬ Promote adherence
99
Environmental influences
```
¬ Assessment of the Home
o Patient’s ability for self-care
o Family support
o Risk factors
o Financial, Transportation Issues
¬ Drug Storage
o Stability
o Proper disposal
```
100
Harris-Kefauver Amendment
¬ This act was in response to the Thalidomide tragedy in Europe
o Pregnant women took thalidomide as a sedative and infants were born with malformations of arms and legs
o Think…could these women have done without a sedative was it medically necessary???
¬ Drugs had to be proved effective before marketing
¬ Prove the drugs offered some benefit
101
Controlled Substances Act
o Regulation of drugs with the potential for abuse
o Scheduling of narcotics I - V
o Schedule I absolute highest abuse potential and no medical use-heroine
o Schedule II – V have accepted medical uses but potential for abuse with schedule II having the highest abuse potential and V the least
♣ Schedule II opioids (Morphine, Hydrocodone)
Schedule 1- never prescribed
Schedule 2- one-time script
Schedule 3, 4, 5- refillable
