Fundamentals of Pharmacology (Pharmocodynamics/kinetics) (LO1)

Question 1

Pharmacokinetics

Answer 1

what the body does to the drug

Question 2

ADME

Answer 2

determine how and how much of a drug arrives at its target body tissues and how long it exerts its therapeutic effect

(A) Absorption
(D) Distribution
(M) Metabolism
(E) Excretion

Question 3

Absorption

Answer 3

refers to the transfer of medication from its site of administration into the body to specific target organs and tissues

The  rate of absorption  determines the  onset  of action

The extent of absorption  determines the  intensity  of action

Question 4

factors affecting the absorption of a medication including

Answer 4

Solubility of the drug

Concentration of the drug

pH of the body

Site of absorption

Absorbing surface area

Blood supply to absorption site

Medication’s bioavailability (the amount of medication that is still active once it reaches it’s target tissue)

Question 5

Distribution

Answer 5

As a drug passes through the body, its form and its concentration in the tissues influences the effect it will have

Plasma protein binding is an important mechanism of distribution

Question 6

bound drug

free drug

Answer 6

bound drug: Plasma protein binding is an important mechanism of distribution.

Drugs are bound in variable degrees to proteins or become stored in fatty tissues

free drug: Only those drug particles that are not bound can be active in the cells

Question 7

metabolism (biotransformation)

Answer 7

changes a drug into forms that can be used by the body or which can be readily excreted (or both)

Metabolism occurs immediately and most often in the liver.

first pass effect: the liver inactivates some medications and some can only be given parenterally

Question 8

Excretion

Answer 8

A drug and its metabolites must be excreted

If a drug is excreted more slowly than it is administered, accumulation occurs causing adverse effects and toxicity.

Question 9

Drug Half-Life

Answer 9

represents the time required for the amount of the drug in the blood serum to diminish by one-half

the concentration (M) of a drug in the blood during a period of time after administration of a single dose

Question 10

The  minimum effective concentration (MEC) or therapeutic index

Answer 10

is a term indicating the lowest concentration of drug in the blood able to produce a therapeutic effect

useful in determining adequate dosages

Question 11

The therapeutic range describes

Answer 11

the range between MEC and the toxic concentration where the drug can seriously harm the client

Question 12

Onset of Action

Answer 12

is the time after administration when the drug reaches the MEC and begins to produce its effects

Question 13

Principles Related to Onset of Action

Answer 13

Route of administration

sometimes a loading or priming dose is given to achieve the MEC quickly

Some drugs have a latency period

peak effect  occurs when blood level is highest

Question 14

The duration of action

The termination of action

Answer 14

–The duration of action–
is usually defined as how long the medication can be expected to remain above the minimum level to provide the effects

it is the time the blood level is above the MEC

-The termination of action-
the amount of time after the concentration level falls below the minimum level to the time it is eliminated from the body

Question 15

Duration of action of :

• fentanyl (Sublimaze®),
• meperidine (Demerol®),
• morphine,
• acetaminophen (Tylenol®),

Answer 15

fentanyl (Sublimaze®), 1–2 hours

meperidine (Demerol®), 2–4 hours

morphine, 3-7 hours

acetaminophen (Tylenol®), 4–6 hours

Question 16

Principles Related to Duration of Action

Answer 16

Short acting drugs must be given frequently.

Duration of action can be maintained by giving drugs at regular intervals (maintaining the blood level).

Duration can be used to help predict the time of next dose.

Occasionally a drug’s effects may persist even after it has been excreted.

Duration is influenced by pharmacokinetics and can vary with different routes of administration.

Question 17

Sites of Elimination

Answer 17

Kidneys (main site of elimination)

GI tract

Perspiration

Respiration

Question 18

Pharmacodynamics

Answer 18

what the drug does to the body

Question 19

Drugs either alter the ——- —- or change the —— — — — —-

Answer 19

Drugs either alter the cell environment or change the rate of cell functions

Question 20

the receptor theory of drug action

Answer 20

Drugs “attach” to cells because their molecular structure matches

All cell receptors will be exposed to the drug circulating in the blood stream but only those that fit (visualize a lock and key) will bind to each other

If many receptors are available, we can increase the drug dosage and thus drug effect.

If few receptors are available, increasing the drug dosage will have no effect.

Question 21

the cell is said to be receptive to the drug if…

Answer 21

If at least three sites on the surfaces of both drug and cell match

Question 22

what are receptors usually made of

Answer 22

cellular proteins or nucleic acids but can be enzymes, carbohydrate residues, and lipids

Question 23

Agonist

Answer 23

a drug that directly alters the rate of a cellular process

Question 24

Affinity for the target tissue

Answer 24

An agonist has a natural tendency to bind with the receptor

Question 25

Efficacy

Answer 25

ability to initiate drug action

Question 26

Partial agonists 

Answer 26

are agonists that produce only moderate effect. They occupy a receptor site and produce moderate effect prevent any other drug from binding to those receptor sites.

Question 27

Antagonists

Answer 27

do not alter cellular rates or environments.  they compete with agonists to occupy the same receptor site If successful in binding more tightly, the antagonist will prevent the agonist from acting Antagonists are often given to act as antidotes excreted more rapidly than the agonist they oppose, therefore have short-lived actions and must be administered repeatedly to prevent toxicity from recurring

Question 28

Numerous factors affect an individual's response to drugs, including:

Answer 28

``` Age Weight Gender Environment Time of administration Condition of the patient Genetic factors Psychologic factors ```

Question 29

Types of Responses

Answer 29

predictable unpredictable iatrogenic

Question 30

Predictable response

Answer 30

extensive research to determine the therapeutic action (desired effect) of a drug in order for a response to be classed as predictable it must have occurred in 50% of the population going to be some potential negative results that may occur (side effects) Through research and testing, most side effects can be anticipated

Question 31

Unpredictable response

Answer 31

If the response seen is unique to that patient and not seen in other patients in a similar setting, the response is classed as an  idiosyncrasy When medications are given in successive doses or in conjunction with other medications, we can see unpredictable responses as well

Question 32

 idiosyncrasy

Answer 32

an abnormal or unusual response to a drug

Question 33

Tolerance

Answer 33

decreased effects of a drug due to long term use These patients will build a tolerance to that medication resulting in the need for a higher than normal dose to achieve the same result

Question 34

Cross-tolerance

Answer 34

drug tolerance in which patients who takes a medication for an extended period of time can build up a tolerance to other medications in the same class

Question 35

Tachyphlaxis

Answer 35

condition where patient rapidly becomes tolerant to a medication

Question 36

Drug dependence

Answer 36

a physical or emotional need for drug

Question 37

Cumulative effect

Answer 37

occurs when several does of a medication are administered or when absorption occurs more quickly than elimination If repeat doses are given too quickly, a cumulative effect may result, causing possible nontherapeutic effects

Question 38

Summative effect

Answer 38

the process where multiple medications can produce a response that the individual medications alone do not produce If two medications of similar effect are given to a patient

Question 39

Synergism

Answer 39

combined action of two drugs that is greater than the sum of their individual responses

Question 40

Potentiation

Answer 40

enhanced action of the drug by another administered concurrently

Question 41

Iatrogenic response

Answer 41

is an adverse condition that is inadvertently induced in a patient by the treatment given An example of this would be a patient developing an urinary tract infection after the insertion of urinary catheter.

Question 42

in the metabolic phase The liver can act on a drug in 2 phases

Answer 42

Phase1: the enzymes may oxidize the drug or bind it with oxygen molecules and can also hydrolyze the medication; both causes medication to be more soluble with water Phase 2: the medication molecules combine with a chemical found in the body (known as conjugation reaction)

Question 43

excretion occurs primarily through the kidneys 3 mechanisms

Answer 43

Glomelur filtration Tubular secretion Partial reabsorption

Question 44

Glomelur filtration

Answer 44

a passive process in which blood flows through the glomeruli of the kidneys a differential in pressure forces waste away from the blood into the capsule where it is transported for excretion

Question 45

Tubular secretion

Answer 45

an active transport process in which medications are bound to specific transporters aiding in their elimination

Question 46

Partial reabsorption

Answer 46

this occurs when some amount of the drug is reabsorbed after being filtered

Question 47

Medications cause their action on the body by four mechanisms:

Answer 47

They may bind to a receptor site They may change physical properties of cells They may chemically combine with other chemicals They may alter a normal metabolic pathway

Question 48

A medication molecule witll have 1 of 2 effects when it binds to a receptor site

Answer 48

It may stimulate the receptor site to cause the response it normally does (agonist) It may block the receptor site from being stimulated by other chemical mediators and inhibit the normal response (antagonist)

Question 49

The autonomic nervous system

Answer 49

is composed of nerve fibers that send impulses from the CNS to smooth muscles, cardiac muscles, and glands

Question 50

The autonomic nervous system (ANS) consists of two further subdivisions:

Answer 50

Parasympathetic  nervous system Sympathetic  nervous system

Question 51

Nerve fibers associated with the parasympathetic system originate

Answer 51

from the spinal cord at the level of the cervical and sacral regions

Question 52

Parasympathetic nervous system is responsible for actions such as:

Answer 52

Decreased heart rate Decreased cardiac contractile force Decreased blood pressure Increased circulation to digestive organs Increased peristalsis Constriction of the pupils Bronchoconstriction

Question 53

The principle neurotransmitter of the parasympathetic nervous system is

Answer 53

acetylcholine ``` uh · seh · tuhl · kow · leen ```

Question 54

acetylcholine

Answer 54

Acetylcholine is very short lived. within seconds of release it is deactivated by another chemical called acetylcholinesterase

Question 55

Within the parasympathetic nervous system there are two main types of acetylcholine receptors

Answer 55

nicotinic and muscarinic

Question 56

Muscarinic receptors

Answer 56

are primarily responsible for parasympathetic overactivity responses

Question 57

Muscarinic responses and what reverses them

Answer 57

including bradycardia, miosis (pinpoint pupils), sweating, blurred vision, tearing, wheezing, SOB, coughing, vomiting, abdominal cramps, diarrhea atropine reverses them

Question 58

nicotinic receptors

Answer 58

are primarily responsible for sympathetic overactivity response and neuromuscular disfunction causes muscular contractions opened by nicotine

Question 59

nicotinic responses

Answer 59

responses include tachycardia, hypertension, dilated pupils, muscle fasciculation (involuntary twitching etc) and muscle weakness

Question 60

cholinergic receptors

Answer 60

these receptors respond to acetylcholine nicotinic and muscarinic

Question 61

parasympathomimetic  or cholinergic agonists

Answer 61

producing effects that resemble (mimic) the stimulation of the parasympathetic nervous system If a medication binds to and stimulates those receptors

Question 62

parasympatholytic  or anticholinergic

Answer 62

blocking effects or producing effects that resemble interruption of the parasympathetic nervous system If a medication blocks the actions of the parasympathetic nervous system ex: atropine

Question 63

Nerve fibers associated with the sympathetic system originate

Answer 63

from the spinal cord at the level of the thoracic and lumbar regions

Question 64

Sympathetic nervous system is responsible for actions such as:

Answer 64

Increase heart rate Increase blood pressure Peripheral vasoconstriction Increase circulation to vital organs Sweat gland stimulation

Question 65

The principle neurotransmitters of the sympathetic nervous system are

Answer 65

catecholamines  norepinephrine  epinephrine

Question 66

Within the sympathetic nervous system there are two main types of receptors

Answer 66

adrenergic  and  dopaminergic.

Question 67

Dopaminergic receptors

Answer 67

are believed to cause renal, coronary, and cerebral artery dilation

Question 68

Adrenergic receptors

Answer 68

are the receptors that are most common within the sympathetic nervous system the receptors stimulated by prehospital medications

Question 69

Adrenergic receptors 4 classes

Answer 69

Alpha1 Alpha2 Beta1 Beta2

Question 70

where are the following receptors primarily located Alpha 1 Alpha 2 Beta 1 Beta 2

Answer 70

Alpha 1: on peripheral blood vessels Alpha 2: on nerve endings Beta 1: within the cardiovascular system Beta 2: on bronchial smooth muscle

Question 71

Alpha 1 stimulation results in:

Answer 71

Peripheral vasoconstriction Mild bronchoconstriction Increased metabolism Stimulation of sweat glands

Question 72

Alpha 2 stimulation results in:

Answer 72

Control release of neurotransmitters

Question 73

Beta 1 stimulation results in:

Answer 73

Increased heart rate (positive chronotropic) Increased strength of cardiac contraction (positive inotropic) Increased cardiac conduction (positive dromotropic)

Question 74

Beta 2 stimulation results in:

Answer 74

Bronchodilation Peripheral vasodilation

Question 75

sympathomimetic  or adrenergic agonists

Answer 75

If a medication binds to and stimulates any of the adrenergic receptors

Question 76

what do sympathomimetic or adrenergic agonists do

Answer 76

producing effects that resemble the stimulation of the sympathetic nervous system

Question 77

sympatholytic or adrenergic antagonist

Answer 77

blocking effects or producing effects that resemble interruption of the sympathetic nervous system

Question 78

Selective beta blockers

Answer 78

bind and block only beta 1 or beta 2 receptors

Question 79

non-selective beta blockers

Answer 79

would block both beta 1 and beta 2 receptors