Anesthesiology Quiz 1 Drugs (AH) Flashcards
1
Q
When would you give pre-medication depending on the route of administration?
A
IV: 5-10mins, IM: 15-45mins, PO: 60min (rarely used)
2
Q
What are the major classes of drugs used for pre-medication?
A
Phenothiazines, Butyrophenones, Alpha2-adrenoceptor agonists, Benzodiazepines, Opiods, Anticholinergics, Ketamine, Other (antibiotics)
3
Q
What phenothiazine is most commonly used?
A
Acepromazine
4
Q
What receptors does Acepromazine act on?
A
Blocks D (dopmamine) receptors, Blocks A1-adenoreceptors
5
Q
Acepromazine blocking the D receptors leads to what desirable effects?
A
Sedation (variable), Is also an antipsychotic
6
Q
What effects are the result of Acepromazine’s action on the A1-adrenoceptors?
A
Vasodilation and hypotension. –> HR may slightly increase with a drop in BP
7
Q
How is Acepromazine administered?
A
IV - onset up to 20mins. IM, SC - up to 45 mins. Oral: dogs-> tablets, horses –> paste
8
Q
When do the effects of acepromazine peak?
A
40 mins
9
Q
How is Acepromazine metabolized?
A
By the liver, slowly –> 4-6 hour duration
10
Q
What are the effects of Acepromazine on the CVS?
A
vasodilation, hypotension +/- slight increase in HR, ↓ PCV (sequestration in spleen), chatecholamine induced arrythmias ↓, inhibits platelet aggregation
11
Q
How does acepromazine effect excited animals?
A
excited animal –> epi release –> paradoxical vasodilation
12
Q
What breed shouldn’t be given Acepromazine and why?
A
Boxers (esp in europe and california). It can induce bradycardia and collapse
13
Q
What are the clinical uses for Acepromazine?
A
Pre-med in SA and horses, Combine with opiods/ alpha2-agonists, horses - avoid ataxia (decreases mm movement), PO - long term sedation
14
Q
What are the contraindications for Acepromazine?
A
Boxers (esp in europe and california)–> It can induce bradycardia and collapse. Breeding Stallions. Animals with hypotension, anemia, bleeding disorders. Animals prone to seizures –> it may lower the theshold but not enough data.
15
Q
Does Acepromazine have analgesic effects?
A
No
16
Q
Does acepromazine induce vomiting?
A
No, it is an anti-emetic
17
Q
What can acepromazine cause in horses?
A
Piokilothermia, priapism
18
Q
What effect does Acepromazine have of the resp system?
A
minimal effects
19
Q
What are the two Butyrophenones?
A
Droperidol = innovar-vet, Azaperone = stresnil, suicalm
20
Q
Which other class of pre-med drugs are Butyrophenones similar to?
A
Phenothiazines
21
Q
How is Azaperone used clinically?
A
Used in combination with ketamine for anaesthesia in aggressive pigs.
22
Q
What are the major A2-adrenoceptor agonisis used in vet met and in what species are they used?
A
Romifadine - horses, Detomidine - horse/cattle, Medetomidine & Dexmedetomidine - SA and can be used in others, Xylazine - all
23
Q
Clinical uses of Alpha2-adrenoceptor agonists?
A
Protent sedative and analgesic
24
Q
On what receptors do Alpha-2 adrenoceptor agonists act?
A
Post-synaptic A1 and A2, Pre-synaptic A2
25
What effects do a2-adrenoceptor agaonists produce when acting on post synaptic A1 and A2?
Vasocontriction, vagal tone increase --> relex bradycardia
26
What effects do a2-adrenoceptor agonists produce when acting on post synaptic A2?
Decrease NE release and sypathetic tone, prolong braycardia
27
Rank selectivity of A2-adrenoceptor agonists from least to most selective
Xylazine < Detomidine < Romifidine < Medetomidine < Dexmedetomidine
28
How does selectiviy alter A2-adrenoceptor agonists effects?
Increases sedation and analgesic effects
29
Which last longer with A2-adrenoceptor agonists, sedation or analgesia?
Sedation
30
Do A2-adeno agonisist cause emesis?
yes
31
Why shouldn't you use an A2-adeno agonist in a blocked male cat?
They inhibit ADH production --> diuresis
32
What effect do A2-adeno agonists have on Resp system?
depresses resparatory system at high doses
33
What species is senstitive to Xyalazine?
Ruminants
34
What can you give to counteract bradycardia with A2-adeno agonisists?
Atropine (carefully), but only in healthy animals. Atropine increases HR which fights against increased pressure --> exploded heart in compromised patient.
35
If you were worried about ataxia in horses, which A2-adeno agonist would you use?
Romifidine --> less ataxia in horses
36
CV effects of A2-adeno agonists?
Bradycardia/arrythmia (1* and 2* AV blocks), vasoconstriction followed by BP decrease, Pale MM, CO decreased
37
Horses may develop colic from A2-adeno agonists, why?
Decreases GI motility
38
What SE of A2-adeno agonists?
Vomiting ( bad for GDV), Decreases GI motility (Colic in horses), sheep -->Hypoxemia and pulmonary edema, Pregenant cows --> uterine contractions, Increased intercranial pressure (bad for head trauma), Startle response, Inhibition of insuline release -->
39
What are the three A2-antagonists?
Atipamezole, Yohimbine, and Tolazoline (only effective for xylazine)
40
How much Atipamezole should be used when reversing Met or Dex?
equal volumes
41
Off lable use for Atipamezole?
Use in horses and wildlife
42
How should Atipamezole be administered?
IM 5-10min, or very slowly via IV
43
List the main Benzodiazepines
Diazepam, Midazolam, Zolazepam( +tiletamine)
44
What effects do Benzodiazepines have on the CNS?
Enhanced GABA binding --> open Cl- channels --> decrease in CNS APs.
45
what does the decreased CNS activity produced by Benzodiazepines produce?
Anti-anxiety effects, anti-convulsant, decreased ICP, Amnesia
46
Do Benzodiazepines produce analgesia?
no
47
what are the effects on CV and Resp for Benzodiazepines?
CV: no depression, Resp: mild dose related resp. depression
48
Clinical uses of Benzodiazepines?
Sedation of sick, pediatric, or geriatric patients (won't produce enough sedation in healthy patients), Combo with other drugs to reduce amount of other drugs needed, Anti-convulsants
49
Which is the better drug, midazolam or diazepam and why?
Midazolam is better: Water soluble --> IM injection, no active metabolites --> less cummulative, shorter acting time but 2X as potent. Diazepam: reacts with light, not water soluble --> IV only (painful), 2 active metabolites, absorbs to plastic
50
Benzodiazepine antagonist?
Flumazenil
51
What type of antagonist is Flumazenil?
Competative antagonist --> reversal is reversable
52
Indications for Flumazenil?
Benzo overdose, prolonged sedation, equine recovery
53
Name a centrally acting mm relaxant used mostly in LA?
Guaifenesin
54
What are the CV/ Resp effects of Guaifenesin>
minimal depression for both. (mm without resp depression = good)
55
What other drugs are often combined with Guaifenesin when it is given in horses?
Thiopental or Ketamin
56
How is Guaifenesin administered?
IV only. Takes a large volume --> TIVA with Ketamine and Xylazine
57
SE of Guaifenesin?
Hemolysis and thrombophlebitis
58
What group of drugs are considered the "gold standard" for analgesia?
Opioids
59
What receptors do Opiods act on and what is the resulting effect?
μ (OP3) - analgesia, moisis, eupphoria, resp. depression, inhibition of gut motility. κ (OP2) - analgesia, sedation, miosis. Δ (OP1) - analgesia, resp. depression
60
Where are Opiod receptors found?
all over, increased in areas of injury
61
Opiod CNS effects?
Analgesia, Dogs - mild sedation, antitussive, Cats/Horses- excitement and increased locomotor activity, Cats - hyperthermia, Dogs/Cats - nausea/vomiting,
62
What do opioids depress?
respiration, GI motility, HR with high doses
63
Which opioids release histamine?
Morphine and Meperidine IV --> hypotension and reflex tachycardia
64
Which opioids cause emesis?
Morphine, hydromorphone, ocymorphone
65
Which opiods are unlikely to cause emesis?
Butorphanol, buprenorphine, meperidine, methadone, fentanyl
66
How is morphine used?
As a baseline analgesic for severe pain
67
Morphine in cats?
Slow elimination and causes euphoria/disphoria in cats
68
Methadone has what additional MOA?
NMDA antagonism --> additional analgesic mechanism
69
What route of admin should you avoid with Meperidine and why?
No IV use - histamine release
70
Is Meperidine short or long acting?
short
71
Does Meperidine cause emesis?
unlikely
72
Uses for Fentanyl?
CRI for surgery, intraoperative bolus, rapid onsetsetitive if IV or IM, rapid sequnce induction
73
How long does a fentanyl patch last for?
72 hours about
74
What can you do if a fentanyl patch isn't providing enough analgesia?
Add another M agonist
75
How do you prepare a patient for a fentanyl patch?
shave but don't scrub - you need the oils in the skin for absorption.
76
Why are fentanyl patches useful?
Long duration
77
What are the drawbacks to using fentanyl patches?
variable time to onset, variable plasma conc., poor alternative to opioid CRI, potential for abuse (by owners)
78
Remifentanil is indicated in what type of patient?
Patients with liver problems. Metabolized by plasma esterases instead of hepatic
79
How long does Remifentanil last?
3-4mins, ultra short acting. Give something about 20mins before stopping so keep analgesia going
80
Buprenorphine acts on what receptors as an agonist?
Partial M agonist
81
Buprenorphine timing?
slow onset, long duration of action 4-6h
82
SE of buprenorphine?
minimal
83
Burorphanol receptors?
M antagonist, K agonist
84
What is butorphanol good for?
Only a weak analgesic but good sedation and antitussive with minimal SE
85
List 3 opioid antagonists
Naloxone and Naltrexone (complete), Butorphanol (partial)
86
Which opiod is most commonly used in horses?
Butorphanol
87
What behavioral modification can occure in unsedated horses as a result of IV administered opioids?
box walking
88
What does Neuroleptoanalgesia mean?
Sedative + opioid
89
What is neuroleptoanalagesia used for?
Preanesthetic medication (ace + morphine), restraint for minor procedures
90
List 4 anticholinergic agents used in pre-med
Atropine, Glycopyrrolate, Scopolamine (Hyoscine)
91
What is the main use for anticholinergic agents?
for treatment of bradycardia caused by vagal stimulation (brought on by opioids)
92
Effects of Anticholinergics?
increased HR, Reduce salivation, Reduce gut motility (colic), Dilate pupils (--> panic in horse/cat), Relax bronchial smm.
93
Which anticholinergic crosses the BBB?
Atropine
94
Which anticholinergic is preffered for rabbits? Why?
Glycopyrrolate. Rabbits have atropine esterase --> very short acting.
95
Dosages for atropine differ in what spp?
Ruminants need a very high dose
96
Which anticholinergic produces and initial drop in HR when given IV?
Atropine
97
Indications for injectable anaesthetics?
Induction of general anesthesia, maintenance of anesthesia (CRI/Bolus), Balanced anesthesia, TIVA, to provide sedation (sm amount of propofol)
98
What are some of the most important characteristics of an ideal inj. anesthetic?
Rapid onset, high lipid solubility --> crosses BBB, no accumulation --> rapid recovery, high therapeutic index, no active metabolites, no endocrinologic effect, min CV/resp depression, no pain on injection.
99
How do you calculate a dose for an obese patient?
Use ideal weight
100
List 3 barbituates and what they are used for
Thiopental - induction in SA (short acting), Pentobarbital - euthanasia, Phenobarbital - long acting, anticonvulsant
101
How do you reconstitute thiopental
with sterile water. Forms a very alkaline solution and can be extremely irritating to tissues.
102
What is the only way to admin thiopental?
via IV cath. Necrosis if perivascular
103
What must you do before admin or thiopental?
remove LRS and flush. LRS + thiopental --> precipitate.
104
Main indications for Thiopental?
Anesthesia in SA, induction in horses when combined with guaifenesin --> reduced ataxia, bolus during maintenance in horses (emergency for when horse is waking up)
105
contraindications for Thiopental?
Patients with hepatic Dz, Greyhouds (can't metabolize), neontal/ pregnant animals, cachexic animals, spenectomy. Not used for maintenance due to accumulation.
106
Which inj. Anesthetic is most commonly used?
Propofol
107
What about the way propofol is prepared makes it less economical?
Propofol is prepared with soy and egg products --> bact growth --> discard after 24 hours (new formula lasts 28 days)
108
Is propofol a tissue irritant?
no
109
Clinical uses for propofol?
Induction (short acting) in dogs and cats, can be used in sm. Ruminants but usually not approved.
110
When using propofol, what do you need to be ready to do?
be ready to intubate and ventilate.
111
Propofol CVS/Resp
CVS - hypotension Resp - depression, apnea.
112
Does propofol provide analgesia?
no
113
Effects on CNS?
anticonvulsant and neuroprotectant
114
Propofol and cats?
Not a good idea. Reduced capacity for glucuronidation --> prolonged recovery. Toxic injury to feline HB --> blood issues
115
contraindications for Propofol?
hypovolemic patients, HF, hyperlibidemia and pancreatitis, cats (avoid repeated)
116
Can you use propofol for CRI or TIVA?
Yes, minimal accumulation. Suppliment with O2 during repeated doses or TIVA
117
SE during induction for propofol?
excitatory signs
118
What is the main drawback to the classic prep of etomidate?
Perivascular injection causes necrosis and phlebitis
119
What are the drawbacks to lipid emulsion prep of Etomidate?
promotes bact. Growth--> discard w/I 24 hrs
120
Etomidate CNS stuff?
Quickly penetrates BBB, max CNS conc. within 1min
121
Clinical use of Etomidate?
Anesthesia induction in high risk patients. Ideal induction agent for compromised patients (shock patients)
122
What animals should not receive Etomidate?
animals with adrenal issues. Horses and Cattle
123
How should etomidate be administered?
Pain on injection. Use combo of fentanyl, diazepan, etomidate via IV cath.
124
Why isn't etomidate used often in vet med?
expensive, rough indcution, inhibits adrenocortical fnx, hemolysis and hematuria reported, painful upon injection
125
What is Alfaxalone?
It is a neuroactive steroid
126
MOA of alfaxalone?
Hypnosis and mm relax via GABAa
127
Admin of Alfaxalone?
Perivascular injection not painful, no necrosis (pH=7), IV or IM via slow injection. Use premed and analgesic
128
Uses for Alfaxalone?
Indcution and TIVA for dogs and cats.
129
Does Alfaxalone provide analgesia?
no
130
CVS/Resp for alfaxalone?
Hypotension (not as bad as propofol), relex tachycardia. Min resp depression.
131
Alfaxalone SE in cats?
Myoclonus and poisthotonus during recovery
132
Admin of Ketamine
IV, IM, SQ, Rectal, Epidural. Never given alone.
133
What happens if you inject Ketamine perivascularly?
Pain! (pH 2-3) But no necrosis
134
Clinical Uses for Ketamine?
Indcution in many spp. especially in zoo animals, short maintencance, CRI in subanesthetic doses for analgesia, Never use alone.
135
Pros of Ketamine?
Analgesia, amnesia, hypnosis. Different routes of admin. Sympathetic stimulation, Min resp depression, bronchodilation
136
Cons of Ketamine?
Muscle rigidity, Pain on injection, Emergence psychomimetic reactions
137
How should you store Ketamine?
Away from light and heat. Otherwise it is stable
138
Onset of action for Ketamine?
IV- 30-90sec, IM - 10-15min
139
MOA of Ketamine?
NMDA = most improtant receptor --> antagonism in brain and spinal cord. Other receptor sites: opioid, cholinergic, adrenergic, GABAa
140
What is the active metabolit of Ketamine?
Norketamine
141
Does Ketamine accumulate?
Yes
142
Ketamine CVS?
Unique! Increases in HR BP and CO. Also direct myocardial depression, but stimulatory effects normally predominate.
143
Ketamine CNS
increases ICP, may elicit seizures, swallow and cough reflexes are retained, increases IOP, no eye rotaion --> use eye ointment
144
Does Ketamine have analgesic properties/?
Yes, profound somatic analgesia --> orthopedic pain
145
Besides the BBB, what other barrier does Ketamine cross and what effect does it have when it does?
Placental barier --> decrease in puppy vigor
146
Contraindications for Ketamine?
CV Dz patients, heptic/renal insufficiency, hyperhyerosis (high BP Dz), Neuro problems & head trauma, Caesarean section, increased IOP.
147
Pros of S(+) Ketamine?
Only need 1/2 dose, longer and stronger analgesia, decreased agitation, disorientation and anxiety, faster recover, suggestive of myocardial and neuronal protection
148
How is Tiletamine sold?
As a combo with Zolazepam
149
What is the main difference between ketamine/BZD and Tiletamine?
Tiletamine is longer acting
150
What is recovery like with Tiletamine?
Rough and long. Zolazepam wears off first --> mm rigidity, excitations and seizures
151
Tiletamine clinical use?
Indcution for many species.
152
Admin of Tiletamine?
IV/IM (painful)
153
Which pre-med drugs provide analgesia?
A2-agonists, opioids
154
Which pre-med drugs do not provide analgesia?
Acepromazine, Benzodiazepines, Guaifenesin
155
Which inj. anesthetics do not provide analgesia?
Propofol, Etomidate, Alfaxalone?
156
Which drugs have minimal CV/Resp effects?
Resp only: Alfacalone, Ketamine. Both: Acepromazine,BDZ (@ clinical dose), Guaifenesin, Opiods (dose dep), Etomidate (dose dep).
157
Which drugs are anti-convulstant
Benzodiazepines, Phenobarbital, Thiopental
158
Which drugs decrease GI motility?
A2-agonists, Opioids
