Ch.19: Sedatives and Tranquilizers (Pablo) Flashcards Preview

Pharmacology > Ch.19: Sedatives and Tranquilizers (Pablo) > Flashcards

Flashcards in Ch.19: Sedatives and Tranquilizers (Pablo) Deck (76):
1

Name 3 phenothiazines

acepromazine
promazine
chlorpromazine

2

Phenothiazine mech. of action

-inhibit DA receptors in CNS--> sedation and tranquilization
-block NE at alpha-adrenergic receptors in periphery

3

What kind of receptors are DA receptors?

G-protein coupled

4

phenothiazine indications

-sedation/tranquil.
-prevention of nausea and vomiting

5

other phenothiazine PK effects

-may see rigidity with high doses
-may lower seizure threshold***
-peripheral vasodilation
-splenic engorgement
-decreased afterload
-low effect on motor activity

6

Why is Ace not safe for Boxers?

can result in bradycardia dn hypertension

7

Important contraindication for Ace***

can lower seizure threshold
-caution with horses and boxers

8

primary use of chlorpromazine

antiemetic in D/C

9

Ace available in what admin routes?

IV, IM, SC, oral

10

phenothiazines have low/high therapeutic index

very high when used in NONanesthetized animals (lowered during anesthesia)

11

contraindicatons of phenothiazines

-dehydration
-hypovolemia (dec. blood volume)
-bleeding
-coagulopathies
-shock

12

3 major effects of alpha-2 agonists***

sedation
analgesia
master relaxation

13

basic structure of alpha-2 agonists

benzene ring with imidazole ring (exception = xylazine, which has a benzene + thiazole ring)

14

Name 6 alpha-2 agonists

xylazine
detomidine
medetomidine
dexmedetomidine
romifidine
clonidine

15

most arrhythmogenic a2 agonist?**

xylazine (due to presence of thiazole ring)

16

mech. of action of a2 agonists (3 main parts)

-mimic the action of NE, therefore inhibiting further release of NE --> sedation
-also stimulates a1 receptor, which can result in adverse effects
-imidazoline receptor stimulation --> mediates hyptoension, antiarrhythmogenesis. Not involved in sedation

17

notable feature of promazine

similar to acepromazine. popular use as oral med

18

Why do you want a2 agonist with high a2 selectivity and low a1 stimulation (high a2:a1 ratio)

will be more selective for sedation/analgesic effects and less adverse effects

19

Xylazine has high/low a2:a1 ratio***

low! It is the least potent and has more neg. side effects

20

most specific alpha-2 agonist that we use***

dexmedetomidine (even though medetomidine is even more specific)

21

Does xylazine have imidazoline receptor stimulation activity?

No, b/c it doesn't have an imidazole ring

22

Indications for alpha-2 agonists

-sedation
-chem. restraint
-preanesthetic
-analgesia
-emesis

23

CNS effects of alpha-2 agonists

-profound sedation via locus coeruleus stim.
-paradoxical excitement possible in less specific a2 agonists
-anesthetic sparing effect

24

CV effects of alpha-2 agonists***

-biphasic response:
Phase 1:
-activation of central a2 receptors --> dec. sympathetic outflow, inc. parasym. tone.
-activation of peripheral a1 and a2 receptors --> vasoconstriction, hypertension, reflex bradycardia
Phase2:
-dec. HR and BP (due to dec. NE), dec. cardiac output
(May see 2nd degree AV block)

25

effect of combining a2 agonist with anticholinergic agent

-increased risk of dysrhythmia
-hypertension
-cardiac output not normalized

26

Respiratory effects of alpha-2 agonists

-mild resp. depression
-cyanosis

27

xylazine in sheep

-can result in pulmonary edema and hypoxemia
-pulmonary macrophage activation --> damage endothelium

28

Musculoskeletal effects of alpha-2 agonists

-muscle relax
-twitch possible if given IV

29

Gastrointestinal effects of a2 agonits

-xylazine: vomiting
-reduced GI motility, acid secretion

30

Renal effects of a2 agonists

-diuresis (inhibit ADH, inc. Na excretion)
-dec. renin
-dec. bladder capacity

31

endocrine effects of a2 agonists

-dec. catecholamine lvls
-dec. stress response

32

metabolic effects of a2 agonists

-hyperglycemia (due to decreased insulin release)

33

Repro effects of a2 agonists

xylazine: premature parturition in cows
myometrial contraction in non-gravid uterus
decreased myometrial contraction at low doses only

34

thermoregulation effects of a2 agonists

-dec. body temp

35

a2 agonists help/hurt equine recovery from inhalation anesthesia

help

36

a2 agonists and analgesia

-profound analgesia

37

first a2 agonist used in vet med

xylazine

38

which animals are sensitive to sedative effects of xylazine?

cattle, ruminants

39

Why do different species have different sensitivity to xylazine

differences in G-protein signaling pathways

40

important chars. of detomidine*

-approved in horses**
-longest duration of action**
-higher a2:a1 ratio than xylazine

41

important chars. of medetomidine*

-can be used to tx emergence delirium in SA following anesthesia**
-provides sedation, anxiolysis, analgesia

42

important chars. of dexmedetomidine

-similar to medetomidine, but w/ higher HR/CO

43

chars. of Romifidine*

-produces less ataxia in horses than xylazine**
-longer duration of sedation than xylazine

44

chars. of clonidine*

-older human agent**
-not used in vet med

45

adverse effects of a2 agonists

-sudden arousal from sedation
-vomiting
-hyperglycemia
-diuresis

46

contraindications of a2 agonists

poor CO

47

3 a2 antagonists

tolazole
yohimbine
atipamezole

48

a2 antag. mech. of action

-REVERSAL of sedation, anxiolysis, analgesia, CV changes induced by a2 agonists

49

yohimbine best reverses which drug?**

xylazine

50

atipamezole best reverses which drug?**

dexmedetomidine and medetomidine

51

tolazoline reverses what?*

xylazine in cattle and SR

52

list yohimbine, tolazoline, and atipamezole in order of increasing selectiving for a2 receptors

tolazoline < yohimbine < atipamezole

53

adverse effects of a2 antagonists

-CNS excitement
-vasodilation
-tachycardia
-CV collapse
-delirium, aggression

54

Benzodiazepine mech. of action

-enhance GABA receptor --> Cl channel opening --> hyperpolarization --> sedation

55

indications of benzos*

-preanesthetic
-anticonvulsant
-m. relaxant
-phobia

56

CNS effects of benzos*

-paradoxical excitement**
-dec. cerebral blood flow/O2 consumption
-anticonvulsant

57

CV effects of benzos*

-minimal CV depression at clinical doses**
-high doses --> dec. MAP, inc. CO

58

Resp. effects of benzos*

-mild resp. depression

59

MS effects of benzos

-m. relax
-ataxia
-can cause agitation in horses

60

T/F: benzodiazepines can cause pain on admin*

T (due to propylene glycol vehicle)

61

Do benzos cause analgesia?

NO

62

Diazepam vs. midazolam***

-diazepam is lipid soluble, short duration of action, w/ unpredictable absorption IM or SC, can be given rectally.
-midazolam has ~2x potency of diazepam***, is water soluble due to presence of imidazole ring**, has reliable bioavailability IM, IV, SC, has faster onset, and can be given nasally.

63

potency and duration of lorazepam vs. diazepam

lorazepam 10x more potent, and longer duration of action than diazepam

64

chars. of zolazepam*

-similar to diazepam
-only used in combo with tiletamine
-cats recover slower and calmer than dogs

65

benzo adverse effects

-agitation, vocalization, aggression
-hepatic failure in cats following repeated oral admin.
-abstinence syndrome (tremors, etc.) w/ sudden stoppage of tx

66

signs of benzo overdose

-ataxia
-depression
-agitation
-GI upset
-weakness
-tremors
-vocal
-tachycardia/pnea
-hypothermia

67

benzo antagonist drug

flumazenil

68

flumazenil mech. of action

-competitively antagonizes benzos on GABA receptor --> prevents hyperpolarization of postsynaptic memb.

69

PD Effects of flumazenil

-reverses electroencephalographic changes of benzos
-inc. BP
-inc. minute vent. and tidal volume

70

flumazenil adverse effects

-seizure in chronically tx benzo patients
-reduced activity in patients w/o benzo
-inflamm./necrosis when administered perivascularly
-dysrrhythmia

71

name 2 butyrophenone derivs

azaperone and droperidol

72

butyrophenone derivates mech. of action

-neuroleptic effect due to antagonism of D-2 receptors

73

Only FDA drug for sedation in pigs***

azaperone

74

indications for droperidol use

-antiemetic
-preanesthetic med

75

PD effects of butyrophenone derivs

-dec. HR, CO
-dec. Hb due to splenic sequestration of RBCs
-dec. m. tone
NO ANALGESIA**

76

T/F: droperidol used to be in combo with fentanyl

T (due to aggressive behavior)