Pharmacology Flashcards

1
Q

pharmacokinetics

A

what the body does to the drug

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

pharmodynamics

A

what the drug does to the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

non cellular mechanisms by which drugs produce an effect

A
  • physical effects: lacrilube applied to eyes
  • chemical: ranitidine on gastric HCl
  • physiochemical
  • modification of body fluid composition
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

cellular mechanisms by which drugs produce an effect

A
  • physicochemical/biophysical mechanisms
  • cell membrane structure and function mods (insulin)
  • enzyme inhibition
  • receptor mediated effects (opioids)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

molecular targets for drugs

A

receptors- transduce signal from drug
enzymes- activated or inhibited
transporters- carry molecules across membranes
ion channels- open or close
nucleic acid- affect gene transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

ligand definition

A

forms a complex with a bio molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

receptor

A

proteins interact with extracellular physiological signals and convert to intracellular effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

characteristics of 4 types of receptor

A

ligand gated ion channels- miliseconds, ACh
G-protein-coupled receptors- seconds, ACh
kinase-linked receptors- hours, cytokines
nuclear receptors- hours, oestrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

full agonist definition and example

A

able to generate a maximal response after binding to a receptor, high affinity and high intrinsic activity
example: methadone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

partial agonist definition and example

A

drug that has an intrinsic activity of less than 1, receptor occupancy produces a sub maximal effect
example: buprenorphine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

inverse agonist definition and example

A

drug binds and inverses the effect to the endogenous agonist.
example: histamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

antagonist definition and example

A

no effect but blocks endogenous mediators.
example: naloxone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

theraputic index

A

maximum non-toxic dose/minimum effective dose
LD50/ED50
- measure of drug safety
- effective dose can be variable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how do drugs cross membranes

A
  • aqueous diffusion
  • passive lipid diffusion
  • facilitated diffusion
  • pinocytosis (cell drinking)
  • active transport
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

bioavailability definition

A

the fraction of a dose reaching the systemic circulation after administration compared to the same dose administered intravenously

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

principles of drug absorption

A
  • drug molecules are usually small weak acids or bases
  • ionisation determined by pKa of drug and pH of surrounding tissue
  • ionised drug molecules cross by facilitated diffusion or pinocytosis
  • tissue pH can change (infection)
  • absorption influenced by route of administration and drug formulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

routes of administration and absorbance

A
  • IV- fastest route
  • IM- absorption variable
  • SC- slower than IM, unpredictable
  • oral- absorption in small intestine, low lipid solulbilty
  • inhalational
  • epidural/spinal
  • transmucosal (oral and rectal)
  • transepithelial (skin, cornea)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

principles of drug distribution

A
  • apparent volume of distribution= amount of drug administered/plasma conc
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

5 factors determining drug distribution

A
  • protein binding
  • tissue binding
  • organ blood flow
  • membrane permeability
  • drug solubility
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

principles of drug metabolism

A
  • termination of drug effects: primarily biotransformation then excretion
  • most drugs are lipophilic and highly plasma protein bound
  • kidney excrete polar water soluble compounds most easily
  • liver is primary organ of metabolism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

clearance definition

A

the volume of plasma from which drug is completely removed per unit time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

half-life definition

A

the time taken for the plasma concentration to fall 50% of its initial value
rate constant K=clearance/vol of distribution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

hepatic metabolism

A
  1. convert drug to more polar metabolite
    • oxidative, hydrolytic or reductive reactions
  2. conjugation with substrates
    • requires energy
    • resultant more polar compound more readily excreted
    • glucuronidation (not cats)
    • acetylation (not dogs)
    • methylation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

principles of drug excretion

A

biliary excretion, lung excretion, GI tract, renal
- renal excretion most common
- active via tubular secretion or passive by glomerular filtration
- may need to alter dose in animals with renal comprimise

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

bacteriostatic vs bacteriocidal

A

bacteriostatic- arrest bacterial multiplication
bacteriocidal- act primarily by killing bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

mechanisms of action of bacteriocidals

A

cell wall- interferes with maintenance of bacterial cell wall leading to rupture due to osmotic pressures
cytoplasmic membrane- drugs that interfere with the structure of the plasma membrane
nucleic acid metabolism- drugs may interfere directly with microbial DNA or its replication or repair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

principles of antimicrobial therapy

A
  1. make diagnosis
  2. remove barriers to cure
  3. decide whether chemotherapy is necessary
  4. select the best drug
  5. administer the drug in optimum dose and frequency and by optimum route
  6. test for cure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

aims of premedication

A
  • decrease stress and risk of injury to animal and staff
  • produce balanced anaesthesia
    • reduced dose of induction and maintenance agents
  • provide analgesia
  • reduce side effects of anaesthetics (lower dose)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

5 classes of drugs used for premedication

A
  • phenothiazines
  • alpha 2 agonists (analgesic)
  • benzodiazepines
  • butyrophenones
  • opioids (analgesic)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

mode of action of phenothiazines

A

dopamine receptor antagonist in CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

mode of action of alpha 2 agonists

A

alpha 2 adrenergic receptor agonist in CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

mode of action of benzodiazepines

A

enhance effect of GABA at GABA A receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

mode of action of butyrophenones

A

dopamine receptor antagonist in CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

mode of action of opioids

A

inhibits neurotransmitter release

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

phenothiazine licensing and example

A
  • acepromazine (ACP)
  • dogs and cats
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

alpha 2 agonist licensing and example

A
  • dexmedotomidine
  • dogs and cats
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

benzodiazepine licensing and examples

A
  • diazepam (dogs and cats) and midazolam (horses)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

butyrophenone licensing and example

A
  • fluanisone (hypnorm)
  • rabbit
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

opioid licensing and example

A
  • methadone
  • dogs and cats?
40
Q

routes of admin for premedication

A
  • IV
  • IM
  • SC
  • OTM (oral transmucosal)
41
Q

clinical effects of ACP (phenothiazine)

A
  • sedation
  • anxiolytic
  • sedation improved when combined with opioid and when animal is left in quiet environment
  • SC is non-irritant and efficacious
  • peripheral vasodilation- can lead to temp drop
42
Q

ACP (phenothiazine) pharmacokinetics

A
  • onset of effect after IV admin- 10-15mins
    • slower than alpha 2 agonists
  • onset of action after IM admin- 30-40mins
  • duration of action- 4-6hrs
  • liver metabolised
43
Q

clinical effects of alpha 2 agonists

A
  • sedation, analgesia, muscle relaxation
  • use body surface area rather than weight for accurate dose
  • bradycardia, reduced CO
  • individual varied respiratory effects
  • can be emetic in dogs and cats
  • can depress GI activity
  • reduces secretion of insulin
  • renal effects- ^urine production
44
Q

alpha 2 agonist pharmacokinetics

A
  • onset of action after IV admin- 5mins
  • peak effect at 30mins
  • reversable with atipamezole
  • duration of action- 2-3hrs
  • liver metabolised
45
Q

clinical effects of benzodiazepines (BDZs)

A
  • minor tranquillisers, muslce relaxant, anticonvulsant
  • can be unreliable in healthy animals
  • combine with opioid, alpha 2 agonist, ketamine to improve sedation
  • minimal effects on CVS, resp system (mild depression)
46
Q

BDZs pharmacokinetics

A
  • admin via slow IV
  • short plasma half life
  • hepatic metabolism, metabolites are active (prolonged effect)
  • bioavailable when given intranasally (unlicensed)
  • rarely liver failure has been reported in cats
  • reversed using= fulmazenil
47
Q

clinical effects of butyrophenones

A
  • fluanisone
  • only available in comb product with opioid fentanyl hypnorm
  • provides surgical anaesthesia for minor surgery
  • poor muscle relaxation unless combined ith diazepam/midazolam
  • moderate-severe resp depression
48
Q

skip

A

skip

49
Q

possible complications for premedicated patients

A
  • excitement/excessive sedation
  • airway obstruction (vomit/anatomical)
  • CVS effects
  • patient cant compensate for existing/hidden condition
50
Q

anaesthesia definition

A

the reversable production of a state of unconciousness required to preform surgery and diagnostic testing

51
Q

general anaesthesia definition

A

a state of unconciousness produced by an anaesthetic agent with absence of pain sensatoin over the entire body

52
Q

regional anaesthesia

A

insensibility caused by an interruption of sensory nerve conduction in any region of the body

53
Q

local anaesthesia

A

lack of sensation in a localised part of the body

54
Q

sedation definition

A

the allaying of irritability or excitement

55
Q

premedication definition

A

a drug/combination of drugs given prior to the induction of general anaesthesia

56
Q

sequence of events during induction phase

A
  • IV catheter placement
  • pre-oxygenation
  • admin of premed if not already given
  • admin of induction agent
  • security of airway
57
Q

concept of anaesthesia triad

A

3 points of triangle- analgesia, narcosis, muscle relaxation

58
Q

balanced anaesthesia definition

A

anaesthesia produced by smaller doses of two or more agents is considered safer than usual large dose of a single agent

59
Q

brachycephalic breed complications during anaesthesia

A
  • airway block
  • GOR
  • ocular
60
Q

boxer dog complications with acepromazine

A

bradycardia and hypotension

61
Q

collies/sheepdogs and MDR1 gene

A
  • multi drug resistance
  • MDR gene responsible for removing some drugs from brain
  • with MDR1 mutation present, drugs arent removed and cause a build up causing neuro problems
  • do not use ivermectin, butorphanol, acepromazine
62
Q

dobermann and von willebrand factor BMBT

A
  • dilated cardiomyopathy in 50% of over 6yr olds
  • asymptomatic
63
Q

CAPSAF enquiry

A
  • post op complications were looked at in first 48hr period
  • 50% of deaths occured within 3hrs of recovery
  • ET intubation has been associated with increased mortality in cats
64
Q

legislation surrounding anaesthesia

A
  • protection of animals (anaesthetic act)
    • prevents castration, dehorning without anaesthesia
  • misuse of drugs act and misuse of drugs regulations
65
Q

list the injectable agents commonly used to produce anaesthesia

A
  • propofol
  • alfaxalone
  • ketamine
  • tiletamine/zolazepam
66
Q

list the injectable agents commonly used for euthanasia

A
  • pentobarbital
  • secobarbital sodium + cincocaine hydrochloride= somulose
67
Q

criteria of the ideal injectable anaesthetic agent

A
  • rapid onset
  • non irritant
  • minimal cardiopulmonary effects
  • rapidly metabolised and eliminated
  • non-cumulative
  • good analgesia
  • good muscle relaxation
68
Q

propofol pharmacokinetics and pharmacodynamics
- how it meets ideal injectable anaesthetic agent criteria

A
  • GABA agonist
  • rapid onset
  • lipid soluble
  • rapidly metabolised and eliminated
  • non-cumulative
  • highly plasma protein bound
  • muscle relaxation
  • non-irritant
69
Q

propofol- how it doesn’t meet injectable amaesthetic agent criteria

A
  • no analgesia
  • pain on injection
  • post-induction apnoea common
  • hypotension (myocardial depression)
  • heinz body anaemia (RBC break down faster than they can be replaced)
70
Q

alfaxalone pharmacokinetics and pharmacodynamics
- how it meets ideal injectable anaesthetic agent criteria

A
  • steroid anaesthetic
  • high theraputic index (window between effective and toxic dose)
  • non irritant
  • 20% plasma protein bound
  • rapid onset
  • rapid metabolism and elimination
  • non cumulative
  • some resp depression
  • preserves baroreceptor tone
71
Q

ketamine pharmacokinetics and pharmacodynamics
- how it meets ideal injectable anaesthetic agent criteria

A
  • dissociative anaesthetic- NMDA antagonist
  • maintains CV/resp function
  • analgesia/antihyperalgesia
  • non-cumulative through active metabolite nor-ketamine
  • 50% plasma protein bound
  • can be used as TIVA in horses
72
Q

ketamine- how it doesn’t meet injectable amaesthetic agent criteria

A
  • slow onset
  • poor muscle relaxation
73
Q

thiopental pharmacokinetics and pharmacodynamics
- how it meets ideal injectable anaesthetic agent criteria

A
  • barbituate
  • alkaline
  • irritant perivascularily
  • rapid onset
  • highly plasma protein bound
  • moderate CV/resp depression
  • predictable
74
Q

factors that may affect the elimination of an intravenous anaesthetic agent and thus recovery

A
  • drug factors including dose
  • species, breed, age
  • co-morbidities
  • CVS function
  • hepatic function
  • renal function
  • hypothermia
75
Q

principles of TIVA

A
  • reduces exposurre to inhalant anaesthetic agents
  • can be used in the field
76
Q

ideal properties of a TIVA agent

A
  • rapid metabolism and elimination
  • fast onset
  • high theraputic index
  • pharmacokinetics available
77
Q

options for induction of anaesthesia

A
  1. injectable
    - IV
    -IM
  2. inhalant
    - face mask
    - gas chamber
77
Q

advantages for injectable induction

A

IV- quick, less stress for animal, reliable
IM- fairly quick, reliable
SC- easy to admin, less painful than IM

77
Q

disadvantages of injectable induction

A

IV- relies on IV catheter
IM- painful, slower onset
SC- slow onset, lower efficacy

78
Q

advantages and disadvantages of gas chamber induction

A
  • great for smallies
  • easy set up
  • cheap
  • no skill needed
  • stressful for animal
  • difficult to observe
  • risk of exposure to staff
79
Q

advantages and disadvantages of face mask induction

A
  • easy to set up and use
  • can give oxygen, VA quickly
  • doesn’t protect airway
  • increases dead space
  • human exposure
  • not always tolerated
80
Q

why correct positioning is important?

A
  • facilitates placement of tubes, catheters
  • prevents injury to all
  • avoids stiff joints/sores
  • ventilation
  • surgical access
81
Q

options for airway management during anaesthesia

A
  1. face mask
  2. laryngeal mask (LMA)
  3. supraglottic device (V-gel)
  4. ET tube (ETT)
82
Q

prinicples of laryngeal mask

A
  • sits over larynx
  • reduced complications compared to ETT
  • not designed for veterinary use
83
Q

principles of V-gel

A
  • species + weight specific design
  • training needed before use
  • blocks oesophagus (prevents aspiration)
84
Q

principles of ETT

A
  • protects airway
  • prevents atmospheric exposure
    • cuff system
  • murphy’s eye (if main hole is blocked, air can still pass through)
85
Q

confirmation of correct placement of an ET tube

A
  • gold standard= capnograph
  • visualisation of tube between vocal folds
  • condensation inside tube
  • appreciation of air movement
  • don’t press on thorax
86
Q

ideal inhalational agent

A
  • non irritant
  • minimal effects on CVS and resp function
  • non toxic
  • rapid uptake and elimination
  • easily vaporised
  • good analgesia and muscle relaxation
87
Q

MAC definition

A

minimum alveolar concentration
- conc required to prevent purposeful movement in response to supramaximal noxious stimulus in 50% of patients
- decreased by premed, hypothermia, pregnancy
- increased by hyperthermia, young, hyperthyroidism

88
Q

MAC purpose

A

compares potency of agents

89
Q

partition coefficient definition

A

ratio of concentration of a compound in two solvents at equilibrium

90
Q

blood/gas partuition coefficient

A

describes the solubility of a volatile agent

91
Q

oil/gas partuition coefficient

A

higher the coefficient, the more potent the anaesthetic agent

92
Q

factors that affect uptake, distribution and elimination of inhalational agent

A
  • conc in inspired air
  • alveolar ventilation
  • blood/gas solubility
  • CO
  • blood/tissue solubility
93
Q

does isoflurane meet the requirements of an ideal anaesthetic agent?

A
  • profound CNS and resp depression
  • hypotension (from vasodilation)
  • no analgesia
  • rapid uptake and elimination
94
Q

potential risk of volatile gases to vet staff

A
  • haemopoetic and neurological abnormalities
  • effective scavenging can solve this