Module A Flashcards
1
Q
Pharmacology
A
The study of how drugs interact with the body
2
Q
Pharmacokinetics
A
The process that determines the concentration of drug in the body fluids and tissues overtime
ADME
A- Absorption
D- Distribution
M- Metabolism
E - Excretion
3
Q
Pharmacodynamics
A
Study of the action of drugs on target receptors and tissues, receptor binding effects and side effects.
“What the drug does to the body.”
4
Q
Describe Absorption
A
How is the drug absorbed into the body fluids
5
Q
Describe Distribution
A
How is the drug “moved” to where it needs to go
6
Q
Describe Metabolization
A
Some drugs need to be made “active” others need to be made inactive to terminate their effects
7
Q
Describe Excretion
A
Removal of the drug from the body
8
Q
Toxicology
A
Study of poisons and organ toxicity
9
Q
What are the routes of administration of drugs?
A
- Enteral
- Parenteral
- Transdermal
- Inhalation
- Topical
10
Q
Crude Drug
A
Preparation obtained from natural sources. Made by drying or pulverizing a plant or animal tissue or extracting substances from a natural production with the help of hot water or solvent (alcohol)
11
Q
Pure drugs
A
Compounds isolated from natural sources or synthesized in the lab and pharmaceutical preparations
12
Q
What is enetric coatings?
A
Consist of polymers that will not break down in the gastric acid but will break down in the more basic pH of the intestines.
13
Q
Why are enetric coatings used? Example
A
Used to protect drugs that would be destroyed by gastric acid and to slow the release and absorption of the drug when a large dose is given.
Example: antidepressants fluoxetine called PROZAC WEEKLY
14
Q
What is sustained- release (Or extended release? How does it happen?
A
Release the drug from the preparation over many hours.
- Controlled diffusion: rate-controlling mebrane regulates release of the drug from the pharmaceutical product
- Controlled dissolution: inert polymers gradually breakdown in body fluids
15
Q
What is a drug?
A
A natural product, chemical substance or pharmaceutical preparation intended for administration to a human or animal to diagnose or treat a disease
16
Q
What is enteral route of administration?
A
Drugs that are absorbed from the gastrointestinal tract.
Advantage most convenient way to give drugs
Disadvantage results can vary widely because of their interaction with food and gastric acid .
17
Q
What is parental route of administration?
A
Drug administration with a needle or syringe or with an intravenous infusion pump.
- intravenous
- intramuscular
- subcutaneous
*most dangerous because rapid administration of drugs by this route can use toxicity
Advantage intervenous route guarantees 100% bio availability
18
Q
What is transdermal route of administration?
A
Application of the drug to the skin for absorption into circulation
- skin path or ointment
Advantage by first pass metabolism, reliable for drugs that are effective when given in a relatively low-dose and are small enough that are highly soluble and lipid membranes
Disadvantage only medication’s, whose molecules are small enough to penetrate the skin can be delivered via this method releases in 1-7days
19
Q
What is inhalation administration ?
A
By nose or mouth used for gas or aerosol.
It can be systemic or local
20
Q
What is tropical administration?
A
Application of the drug to the surface of the body to produce a localized effect
21
Q
What is nonproprietary
A
Generic or official name of the drug used by healthcare professionals
22
Q
What is proprietary?
A
Trade or brand name of the drug
Registered trademark belonging to a particular manufacture and is used to designate a drug product marketed by the manufacturer
23
Q
What are the advantages of inhalation administration?
A
Smaller doses are needed
On set of drug action is rapid
Drug delivery is targeted to the respiratory system
Systemic effects are minimal or none
Administration route is painless and convenient
24
Q
What are the disadvantages of inhalation administration?
A
Many variables can affect drug delivery and therefore dose
Dose consistency and reproducibility is an issue
Some devices require significant patient coordination
Many different devices are available with varying requirements
25
Bioavailability
The amount of drug that is in the blood (injected or absorbed)
26
What are the drug absorption processes?
Passive (lipid and aqueous) diffusion
Active transport
Facilitated transport
27
Describe passive diffusion
Common process of drug absorption
Contolled by Fick’s Law (involves drug concentration, gradient, and surface area available)
Includes lipid and aqueous diffusion
28
Describe lipid diffusion
A drugs ability to pass through lipid membrane is very important factor in determining how quickly the drug is distributed throughout the body, since all cell membranes are composed of lipids
29
Describe aqueous diffusion
Occurs via passage of drugs through aqueous pores in the cell membranes.
Drugs molecular size determines aqueous diffusion
30
What is active transport?
Requires energy to move the drug into the body circulation
Needs a form of energy and carrier molecules
31
What is facilitated diffusion?
Requires a carrier molecule and does not require energy
32
How is drugs distributed?
Drug distribution is primarily the blood through lymph, fluids and cerebral spinal fluid (CSF)
33
What does drug distribution depend on?
Organ blood flow, plasma protein, binding, drug size and lipids solubility
34
Describe organ blood flow
The greater the amount of cardiac output going to a particular organ, the greater the drug distribution to that organ and the faster, the drugs onset of action
35
Perfusion
The amount of blood flow and organ receives.
Heart, brain, liver, and kidneys are highly perfused organs
36
Describe plasma protein binding
Primary plasma protein, that drugs are reversibly bound to is Albumin.
The amount of binding to the plasma protein is drug dependent and can vary from 10 to 90%
37
Biological availability
The amount of binding
The higher the affinity (liking) of the drug for the plasma protein the less free or inactive drug there is since only the free drug is active (able to act on the drug receptor and have an effect)
38
Describe molecular size
Affecting the distribution of extremely large molecules
39
Describe lipids solubility
Affecting the extent of drug distribution in particular to the brain where the blood brain barrier restrict the penetration of polar and ionized molecules
40
What effect does PH have on drug absorption?
Drugs are either weak acids or weak bases and exist in their ionized or non-ionized forms.
Only non-ionized forms of drugs can penetrate through cell membranes
The amount of ionized to non-ionized drugs is dependent upon the pKa of the drug (the pH at which the drug is 50% ionized and 50% non-ionized) of the environment and whether the drug is a weak acid or weak base.
41
How can drug absorption be prevented? (in relation to pH)
Drug absorption can be prevented by changing the pH of the environment according to whether the drug is a weak acid or a weak base.
This form of treatment is commonly used with drug overdoses
42
What influence drug concentration in the plasma?
Biotransformation and excretion
43
Clearance
A measure of the rate of elimination
44
What is biotransformation of a drug and its purpose?
Bio transformation is the whole process of first pass metabolism. The main organ involved is the liver and the purpose is to make the drug less toxic and water soluble so that it can be eliminated.
45
Prodrugs
Are administered as inactive compounds, and then biotransformed to active metabolite
-Developed because the prodrug is better absorbed than it active metabolite
46
What is the main group of enzymes involved in biotransformation of drugs?
Microsomal cytochrome P450 (CYP) monooxygenase system
47
What is first pass metabolization also known as first pass biotransformation?
A process in which drugs get metabolized in the liver before they enter systemic circulation.
If we want drugs to have a systemic effect, we do not want to have a high first past metabolization whereas if we do not want a systemic effect (pulmonary drugs) , a high first past metabolization is desirable
48
What routes avoid first pass metabolization?
Parenteral, sublingual or buccal, rectal and inhalational routes
49
What is the main organ of excretion?
Kidneys
50
What is excretion?
Removal of drugs from bodily fluids and occurs primarily in the urine
- other routes of excretion from the body include bile, sweat, saliva, tears, feces, breastmilk, and exhaled air
51
Half life
Time required to decrease the plasma concentration of a drug by 50%
52
How pH of urine can alter drug re-absorption?
The pH of urine is altered so that the drug is filtered in ionized and can’t be absorbed
53
What are the steps of renal excretion and an important factor in determining the rate of each one?
1. Glomerular filtration - depends on the level of drug albumin binding
2. Active tubular secretion - depends on competitive inhibitor by other drugs/metabolites
3. Passive tubular reabsorption -depends on tubular pH (ionized forms will not be absorbed)
4. Excretion- depends on urine flow rate
54
Drug clearance (CI)
The volume of body fluid from which the drug is removed per unit time
55
By definition drugs delivered by the IV route have ___% bioavailability
100%
56
In general acidic drugs, bind to plasma ____
Albumin (A is for acid and albumin)
57
Define loading dose and explain how it is calculated
Loading dose is a relatively large initial dose of a drug given to achieve a desired plasma concentration it is calculated as loading dose equals Vd x C
Vd = volume of distribution
C = desired plasma concentration
58
Describe maintenance dose
A dose given to establish or maintain the desired steady state plasma drug concentration.
59
Maintenance doses are designed to maintain a steady state of plasma. Concentration and for convenience are often administered in intervals equal to ____
The drugs half-life.
This will lead to a maximum twofold fluctuation in the drugs plasma concentration, which is seen as acceptable in most cases
60
That’s the four types of drug receptors
1. G protein coupled (receptors)
2. Ligand- gated ion channels.
3. Membrane- bound enzymes.
4. Intracellular (nuclear)
61
Ligand
Neurotransmitter hormones or drugs that have an effect on the body, most mimic or block the action of an endogenous, hormone or ligand.
62
Affinity
Ability of a drug to bind to a receptor or target drug
63
Efficiency
Ability of a drug to activate a cellular effect
64
List three ways that drug receptors are classified
1. Drug specificity
2. Tissue location
3. Primary amino acid
65
Describe non-competitive antagonist
An antagonist that binds to a receptor irreversibly through covalent bonding
66
Describe a competitive antagonist
An antagonist that binds to the receptor reversibly
67
What is an antagonist?
Drugs that have infinity for receptors, but does not have efficacy
68
What is agonist and the two types?
Drugs that have affinity for receptors and efficacy.
1. Full: have affinity and can produce the max response in a tissue and therefore max efficacy.
2. Partial : have affinity, but only produce a submaximal response
69
What is tachyphylaxis?
The short-teem effect of agonist exposure, occurs rapidly
70
Describe down regulation
Consequence of long term effect of agonist exposure. Decrease in density of receptors (binding affinity to ligand decreases)
71
Tolerance
Where a drugs lose it it’s a fact, or a higher dose of drug is needed to produce an effect
72
G protein coupled receptors
Alpha and beta receptors found on vascular, smooth muscle
examples: acetylcholine, norepinephrine histamine, and serotonin
73
Ligand gated ion channels
Large class of membrane proteins that share similar subunits. Ligands mine to these types of receptors and alter the conductance ions through channels.
Examples, nicotinic receptor found on skeletal muscle
74
Membrane bound enzymes
When a ligand binds to this type of receptor, it activates an enzyme within the cell to further alther enzymatic activity within a cell
example insulin
75
Intracellular and nuclear receptors
Found within the cell receptors become activated when the ligand enters the cell
Example: corticosteroids
76
Potency
A qualitative term used to compare different drugs to each other based on median effective dose, which is the dose that produces 50% of the maximum effect
77
Therapeutic index (TI)
Ratio between the median lethal dose (LD50) and median effective dose (ED50)
* reflects the safety aspect of the drug, the higher, the TI, the safer the drug.
78
Compare and contrast, therapeutic injects, and certain safety factors of a drug
Both are measures of drug safety in relation to its potency .
- therapeutic index is a ratio between LD50 and ED50
-certain safety factors is the ratio between LD1 and ED 99 of a drug. It is more restrictive and perhaps more practical measure of the safety of a drug.
79
Explain the difference between phase I, II, III clinical trials
Phase I - drug administered to healthy individual to study Pharmokinetics and pharmacodynamics
Phase II -drug administer to individuals with conditions of study to establish dosing, efficacy, and safe use
Phase III - large-scale trials to study drug therapeutic benefit
80
Steps involved in the development of a new drug
Discovery and characterization of a new drug
pre-clinical studies
IND application
clinical studies
submission of NDA
approval of NDA
post marketing surveillance
81
Role of FDA
Regulates drug development in a IND application must be completed before clinical studies can be started, and NDA must be submitted and approved before the drug can be marketed
82
Excessive pharmacological effects
Produce adverse effects by the same mechanism response for their therapeutic effect on the target organ.
manage by reducing the dose or by substituting a drug that is more selective to the target organ
83
Drug hypersensitivity reactions
Drug allergies, a large number of organ toxicities that range in severity from a mild skin rash to major organ system failure.
84
What are the adverse effects on organs?
Hematopoietic toxicity - bone marrow toxicity most frequent effects are reverse once the drug is withdrawn
Hepatotoxicity - liver toxicity via immunological mechanisms or via their direct effect.
Nephrotoxicity - renal toxicity typically caused by antibiotics often reduces drug clearance
Other organ toxicities- pulmonary toxicity causes respiratory depression via its affect on the brain stamp respiratory centres
Idiosyncratic reaction - unexpected drug reaction caused by a genetically determined susceptibility
85
Additive or summative effect
This means that two drugs given together have an effect equal to the sum of their individual effects
Summarized by the formula 1+1 = 2
86
Synergetic effect
Two drugs given or taken at the same time will have a greater effect than the sum of the individual drugs
Summarized by the formula 1+1 = 3
87
Antagonistic effect
One drug or ligand and prevents the normal effect of receptor stimulation, (competitive antagonist) or where two different ligand have opposite effects at different receptors
88
What factors affect drug safety?
Age disease, pregnancy lactation are biological variables that can alter the response to drugs and patients
89
a.c.
Before meals
90
alt hor
Every other hour
91
bid
Two times a day
92
ć
with
93
cap
Community acquired pneumonia
94
cc
Cubic centimetre
95
et
At that time
96
ex aq
in water
97
g
Gram
98
hs
Bedtime
99
IM
Intramuscular
100
IV
Intravenous
101
nebul
Nebulizer
102
Non rep
No repeats
103
npo
Nothing by mouth
104
pc
After meals
105
Placebo
Inherent substitute
106
po
mouth, orally
107
prn
As needed
108
q
Each, every
109
qh
Every hour
110
qid
Four times a day
111
qod
Every other day
112
qd
Daily, everyday
113
q2h
Every 2 hours
114
q3h
Every 3 hours
115
q4h
Every 4 hours
116
Rx
Prescription
117
Ś
Without
118
Stat
Immediately
119
Tid
Three times a day
120
ED50 is used to measure ____ and if defined as:
ED50 (median effective dose) measures drug potency and is the dose that produces 50% of the maximum effect of the drug.
121
Aqueous diffusion of a drug is limited by _____
Molecular weight (only small molecules can diffuse through aqueous pores)
122
Weekly acidic drugs absorbed best in the ____
Intestines, there is a greater surface area available for diffusion which is more important than acid/base ionization effects
123
Phosphorylation of receptors in response to repeated exposure to ligands is an underlying mechanism of _____
Desensitization
* phosphorylation may reduce the affinity of ligands for receptors, or may mark the receptor for cellular internalization, reducing receptor density on the cell surface
124
Main purpose of biotransformation
Reduce the toxicity of drugs and make them more soluble to facilitate excretion
125
To facilitate excretion of a week base drug. The clinician should target a ____tubular pH.
Acidic.
Drugs cannot be passively reabsorbed in their ionized form, so the ionized weak base will be excreted more readily
126
When GDP is bounded to a G protein, it is _____ (activated/inactivated)
Inactivated
*G protein, alpha subunit activation is marked by GTP binding
127
In the presence of a complete agonist a partial agonist may act as
An antagonist through competitive inhibition
128
And advantage of inhalation route is it has a ____ local effect and a ____systemic effect?
High local effect
Low systemic effect
129
Drugs that have a high fraction, bound to plasma proteins will have a _____ globular filtration rate
Low
130
Describe the difference between one compartment and two compartment models of pharmokinetics
The two compartment model treats, blood plasma and tissues/organs as two separate compartment and describes a third rate constant for determining the movement of drugs between these two
131
What is the importance of AUC in Pharmokinetics?
AUC (area under curve) represents the total amount of drug made available to the circulatory system for therapeutic effect
132
To facilitate excretion of a weak acid drug the clinician should target a ____ tubular pH
Basic. Drugs cannot be possibly reabsorbed in their ionized formed, so the ionized weak acid will be extracted more readily.
133
Describe the distribution and elimination phases of pharmacokinetics
After administration of a drug, there is a rapid decrease in the plasma concentration (distribution phase) as the drug is distributed in body fluids. after that the plasma consultation decreases more slowly as a drug is metabolized and excreted.
134
The primary determinant of drug efficacy is
Receptor affinity
135
Phase I biotransformation involves the processes
Reduction oxidization, and Hydra
136
Biliary excretion tends to only include drugs with a _____molecular weight
High
137
Elimination
Elimination = metabolism + excretion
138
All adrenergic receptors belong to the
G protein coupled receptors (GPCRs)
139
In general, basic drugs bind to plasma ___
Proteins and Beta globulins. (B is for base and beta globulin)
140
Organs receiving the highest portion of cardiac output ____, will receive drugs at the highest rate
Heart brain, liver, kidneys
141
Explain why it would be favourable for drugs delivered by the inhalation route to have a high first past metabolism
We generally want these drugs to have a large local and small systemic effect. Some of these drugs will invariably be ingested enterally. we want there to be a high pass effect on the ingestion fraction to avoid systemic effects.
142
Lipid diffusion is facilitated by a drug having high _____
Lipids solubility
143
Describe fick’s law
The rate of diffusion of a substance is proportional to the concentration gradient and the surface area of diffusion
144
Drugs that are weak _____ absorbed best in the stomach
Acids
145
Why are pulmonary medication’s most often inhalation agents?
Because inhalation provides the highest concentration of drugs to where it is most needed with limited systemic effects
146
Toxicology
Study of poisons and human toxicity
147
Pharmatherapeutics
Use of drugs in the treatment of disease
