Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

N934 Adv Principles Fa 21 > Tocolytics and Uterotonics > Flashcards

Tocolytics and Uterotonics Flashcards

1
Q

tocolytic drugs include (6)

A 
magnesium sulfate
CCB's
beta agonists
nitric oxide donors
cyclooxyrgenase inhibitors
oxytocin antagonists
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

tocolytics inhibit labor by

A

generation or alteration of intracellular messengers or inhibiting synthesis or block action of myometrial stimulant

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

magnesium sulfate MOA

A

alter calcium transport and availability for muscle contraction.
compete with intracellular calcium, reducing myometrial contractility.
hyper polarization of plasma membrane leads to inhibition of myosin light chain kinase activity as magnesium
also depression of motor endplate sensitivity and excitability

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

magnesium relaxes which 3 muscle groups

A

vascular, bronchial, and uterine smooth muscles

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

how does magnesium sulfate treat preeclampsia

A

relaxes vascular smooth muscle decreasing SVR and BP
anticonvulsant
decreases fibrin deposition, improving circulation to visceral organs

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

neonatal side effects for magnesium sulfate administration are rare but include (3)

A

hypotonia
respiratory depression
expect a lower APGAR

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

how to administer magnesium sulfate for the treatment of preeclampsia

A

loading dose of 4-6g IV over 20-30 minutes
infusion of 1-2 g/hour
continued through delivery and up to 24 hours post delivery

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

therapeutic level of magnesium sulfate and side effect to expect

A

4-9mEq/L, 4-8mg/dL

EKG changes: PQ lengthened, QRS widened

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

normal serum magnesium during pregnancy is

A

1.8-3mg/dL

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

at a serum level of 7-9mg/dL, magnesium has this effect

A

anticonvulsant

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

at a serum level of 10-12mg/dL, magnesium has this effect

A

tendon reflexes abolished

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

at a serum level of >12mg/dL, magnesium has this effect

A

respiratory depression

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

at a serum level of 15-20mg/dL, magnesium has this effect

A

SA and AV blocks, respiratory arrest

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

at a serum level of 18mg/dL, magnesium has this effect

A

apnea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

at a serum level of 25mg/dL, magnesium has this effect

A

cardiac arrest

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

what does magnesium do to blood pressure

A

lowers it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what does magnesium do to NMB’s

A

potentiate them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what does magnesium do to alpha agonist drugs

A

antagonize them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

side effects of magnesium sulfate (general list) includes (11)

A 
flushing 
transient hypotension
palpitations
chest pain
nausea
blurred vision
sedation
pulmonary edema
skeletal muscle weakness
CNS depression
vascular dilatation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

treatment priorities for magnesium sulfate overdose include

A

discontinue infusion
secure airway
IV administration of calcium chloride
diuresis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

anesthetic implications of magnesium sulfate includes (4)

A

exaggerated HoTN after administration of epidural or general anesthesia
succinylcholine dose not reduced for intubation but defasciculating doses are not required.
reduce maintenance doses of non depolarizing muscle relaxants
symptomatic hypocalcemia and respiratory compromise have occurred in cases of myotonic dystrophy

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

which CCB is most popular as a tocolytic and why

A

nifedipine because it can be given PO or SL

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

MOA of CCB’s as a tocolytic

A

block influx of calcium ions through cell membrane
block release of calcium from SR
inhibit calcium dependent myosin light chain kinase mediated phosphorylation. leads to myometrial relaxation
also acts on potassium channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

when calcium channel blockers are used as a tocolytic, birth is delayed for how long

A

2-7 days

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

side effects of calcium channel blockers include

A 
HoTN
dyspnea
pedema
tachycardia
HA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

avoid concomitant use of CCB’s with which drug and why

A

magnesium sulfate

enhance NMB effects affecting respiratory and cardiac function

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

anesthetic implications of calcium channel blockers (one having further implications)

A

expect HoTN with administration of neuraxial or GA

potential uterine atony that may be refractory to oxytocin and prostaglandins (which both act through calcium channels)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

if uterine atony occurs on a CCB, what should you administer

A

methergine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

MOA of B2 agonists as a tocolytic

A

stimulation of B2 receptors results in smooth muscle relaxation.
biochemical events lead to inhibition of myometrial contractility, increase in progesterone production.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

MOA of progesterone

A

causes histologic changes in myometrial cells that limit spread of contractile impulsers

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

two common beta 2 agonists

A 
terbutaline
ritodrine (no longer marketed in US)
32
Q

hazards of B2 stimulation includes

A

increased blood sugar and insulin levels in the mom
neonatal hypoglycemia
fetal tachycardia is common

33
Q

hazards of B2 stimulation: increased BG and insulin levels in the mother timeline and electrolyte implication

A

increases within a few hours and returns to baseline within 72 hours
the same happens with potassium- it can reach 3mEq/L

34
Q

hazards of B2 stimulation: neonatal hypoglycemia. side effects/expectations

A

increased insulin secretion in response to hyperglycemia

following delivery, glucose load from mother ceases leading to rebound hypoglycemia

35
Q

side effects of the use of B2 agonists as a tocolytic include (general)

A 
maternal and fetal tachycardia
dysrhythmias
ischemia
HoTN
pedema (rare)
HA
hyperglycemia 
hypokalemia
increased plasma renin and vasopressin
36
Q

anesthetic implications of beta 2 agonists

A

delay anesthesia for 60 minutes to allow the heart rate to decrease
if not possible, all drugs that increase heart rate should be avoided
monitor IV administration due to risk of fluid overload and pedema
treat HoTN with phenylephrine (>) or ephedrine

37
Q

drugs that increase heart rate include (6)

A 
ketamine
atropine
glycopyrrolate
thiopental
pancuronium
etomidate
38
Q

MOA of nitroglycerine

A

nitroglycerine is a nitric oxide donor with a short t1/2
its an endogenous substance necessary for smooth muscle tone
acts by increasing cyclic guanosine monophosphate (cGMP) and therefore inactivates myosin light chain kinases causing smooth muscle relaxation

39
Q

are nitric oxide donors or magnesium sulfate more likely to delay delivery

A

magnesium sulfate

40
Q

side effects of nitric oxide donors include

A

maternal HoTN and HA

41
Q

MOA of cyclooxygenase

A

converts arachidonic acid to prostaglandin H2. substrate for tissue specific enzymes critical to giving birth

42
Q

MOA of prostaglandins

A

enhance formation of myometrial gap junctions which increases available intracellular calcium by raising transmembrane influx and sarcolemmal release

43
Q

MOA of cyclooxygenase inhibitors

A

reduce prostaglandin levels, inhibiting COX enzymes. results in decreased uterine contraction

44
Q

2 cyclooxygenase inhibitors used as tocolytics and their selectivity

A

indomethacin (nonselective)

celecoxib (cox 2 selective)

45
Q

efficacy of celecoxib as compared to magnesium sulfate for use as a tocolytic

A

equal efficacy in preventing preterm birth within 48 hours

46
Q

anesthetic implications of cyclooxygenase inhibitors

A

platelet inhibition associated with nonselective cox inhibitors. transient and reversible, neuraxial anesthesia not contraindicated

47
Q

atisoban class and MOA

A

class: oxytocin receptor antagonist
MOA: blocks normal effects of oxytocin in the uterus. the myometrium does remain sensitive to oxytocin

48
Q

how does oxytocin stimulate contractions

A

by converting phosphatidylinositol triphosphate (PIP3) to inositol triphosphate (IP3).
IP3 binds to protein in SR causing calcium release into cytoplasm

49
Q

why is atosiban not approved in US

A

reports of fetal death are associated with use of this drug before 28w gestation

50
Q

anesthetic considerations for tocolytics in general

A

tocolytic PK and PD knowledge is essential (maternal and fetal physiology implications)
neuraxial preferred over GA (neonate APGAR scores are higher at 1 and 5 minutes)
patients on magnesium sulfate are candidates for neuraxial (careful attention is given to volume status)

51
Q

since magnesium causes vasodilation, what complication is poorly tolerated in those women

A

maternal hemorrhage

52
Q

leading and second leading cause of PPH

A

uterine atony
oxytocin admin (?)
(slide 29????)

53
Q

where is oxytocin produced

A

posterior ptuitary

54
Q

MOA of oxytocin

A

lowers threshold for depolarization of uterine smooth muscle. depolarization is enhanced by activation of calcium channels and increased prostaglandin production

55
Q

synthetic oxytocin chemical makeup, side effects in relation to endogenous oxytocin

A

pitocin/syntocinon are octapeptides

cause fewer side effects than endogenous oxytocin (related to ADH and water intoxication)

56
Q

oxytocin administration

A

20-40units/L of isotonic solution IV over 15-20 minutes

57
Q

uses of oxytocin (2)

A

used prophylactically to reduce blood loss after delivery

infusion at a low controlled rate are used to induce labor

58
Q

anesthetic considerations of oxytocin

A

causes a degree of vasodilation or decreased SVR which can result in significant HoTN and tachycardia.
associated with IV bolus of oxytocin so avoiding boluses is recommended

59
Q

what is the second line treatment for uterine atony

A

ergot alkaloids

60
Q

positive effects of ergot alkaloids in the treatment of uterine atony

A

effective for decreasing postpartum blood loss and PPH

produce tetanic uterine contractions restricting their use during the post delivery period

61
Q

synthetic ergot alkaloid

A

methergine

62
Q

semisynthetic ergot alkaloid

A

ergotrate

63
Q

MOA of ergot alkaloids

A

not clear, thought to be an alpha adrenergic agonist effect

64
Q

methergine dose

A

.2mg IM, contractions occur within minutes of administration

dose may be repeated in 15-20 minutes, total dose .8mg

65
Q

IV administration of methergine can result in these side effects

A

profound HTN (have vasodilators avail)
severe n/v (effect on vomiting center)
cerebral hemorrhage

66
Q

anesthetic implications of ergot alkaloids: do not use in women with

A

preexisting HTN: pregnancy induced or chronic
peripheral vascular disease or ischemic heart disease (MI’s have occurred in women treated with PO our IV ergot alkaloids)

67
Q

second option when methergine is contraindicated (class, drug names)

A

prostaglandins

carboprost, hemabate (15 methylprostaglandin F2a)

68
Q

how effective are prostaglandins in PPH refractory to oxytocin and ergot alkaloids?

A

80-90% effective

69
Q

MOA of prostaglandins

A

increases myometrial calcium levels and subsequently increases myosin light chain kinase activity and uterine contraction

70
Q

hemabate class and MOA

A

250mcg IM or directly into myometrium. repeat q15-30 minutes to a total dose of 2mg
prostaglandin

71
Q

which drug has reduced blood loss at c section and is as effective as oxytocin

A

prostaglandin e1 analog misoprostol

72
Q

misoprostol dose

A

800-10000mcg SL or buccal

73
Q

misoprostol is not preferable to other uterotonics for the active management of

A

3rd stage labor

74
Q

anesthetic implications of prostaglandins

A

all of these drugs have detrimental SE
use of carboprost in women with reactive airway disease can result in bronchospasm, ventilation perfusion mismatch and hypoxemia. monitor oxygen saturation and lung sounds

75
Q

misoprostol can be used in patients with which co morbidities

A

reactive airway disease and HTN

N934 Adv Principles Fa 21 (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions