Sympathomimetic-PDE III Flashcards

1
Q

PDI are heterogenous group of non-catecholamine non-glycoside that exert a competitive inhibitory action of phosphodiesterase enzyme.

A

PDI

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2
Q

Multiple types of phosphodiesterase enzymes exist in different tissues: (5)

A
Cardiac muscle
Vascular smooth muscle
Platelets
Liver
lungs
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3
Q

Selective inhibitors of phosphodiesterase fraction III (PDE III) MOA

A

decrease hydrolysis of cAMP leading to increased intracellular concentrations of cAMP in the myocardium and vascular smooth muscle.

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4
Q

PDI have an indirect effect on what in vascular smooth muscle

A

cyclic guanosine monophosphate-dependent protein kinase

cGMP

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5
Q

PDI in the myocardium have what effect

A

increase intracellular cAMP-increase calcium-increase contractility

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6
Q

what is the effect of PDI and increase vascular smooth muscle increased cAMP- increased calcium

A

leads to smooth muscle relaxation and vasodilation

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7
Q

PDE III inhibitors have positive inotropic effects and smooth muscle relaxation in both arteriolar and venous beds and thus called….

A

inodilator

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8
Q

PDE III isoenzymes exist in airway smooth muscle bronchodilation - do we see this clinical effect

A

is not a predominant clinical effect of the current cardiac-selective PDE III inhibitors.

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9
Q

PDE III inhibitor

contractility and CO effects

A

Increased contractility

Increased CO

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10
Q

PDE III inhibitor

venous capacitance effects

A

Increased venous capacitance (The measure of a BLOOD VESSEL’s ability to increase the volume of BLOOD it holds without a large increase in BLOOD PRESSURE. Thevascular capacitanceis equal to the change in volume divided by the change in pressure.)

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11
Q

PDE III inhibitor

LVEDP, CVP, PCWP, Venous return to the heart, MAP, PVR, SVR

A

Decreased LVEDP
Decreased filling pressure (CVP and PCWP)
Decreased venous return to the heart
Decreased MAP, Pulmonary and Systemic Vascular Pressure

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12
Q

PDE III inhibitor

lustitropic effect

A

Improve the lusitropic (rate of myocardial relaxation) state of the heart

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13
Q

PDE III inhibitor

diastolic effect

A

Diastolic relaxation is facilitated by enhanced calcium removal from the sarcoplasm, thereby improving ventricular filling

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14
Q

PDE inhibitors do they cause arrhythmias

A

rarely

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15
Q

PDE inhibitors preload and after load affects

A

decrease preload and afterload

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16
Q

PDE inhibitors effects on wall tension and myocardial 02 consumption

A

decrease

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17
Q

PDE III inhibitors affect on beta adrenergic receptors.

A

PDE III inhibitors act independently of Beta adrenergic receptors and will increase myocardial contractility in patients with myocardial depression from Beta receptor blockade and in patients who have down regulation of Beta adrenergic receptors and are refractory to catecholamine therapy.

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18
Q

can PDE inhibitors be used with digitalis

A

yes an will not provoke toxicity- The hemodynamic response to selective PDE III inhibitors exceeds that of cardiac glycosides and is synergistic to actions of catecholamines

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19
Q

Bypyridine derivative that acts as a selective PDE III inhibitor and produces dose dependent positive inotropic and vasodilator effects manifesting as increased CO and decreased LVEDP.

A

amrinone (inamrinone)

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20
Q
amrinone effects of
CI
LV stroke index
lv EF
LVEDP, PCWP, PAP, CVP, SVR
HR
A
Increases CI
Increases LV stoke index
Increases LV EF
Decreases LVEDP, PCWP, PAP, Right Atrial Pressure and SVR
Minimal effect on HR
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21
Q

protein binding of amrinone

A

minimal protein bound

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22
Q

amrinone distribution half life

A

1-2min

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23
Q

amrinone excreted unchanged %

A

26-40%

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24
Q

metabolism of amrinone

A

N-acetylation and glucuronidation by the liver

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25
Q

amrinone elimination half time

A

2.6-4.1hr

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26
Q

when is amrinone elimination half time increased

A

heart failure

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27
Q

administration form of amrinone

A

po & IV

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28
Q

what two ways does amrinone increase co

A

inotropic action or vasodilation mechanism

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29
Q

long term oral use of amrinone results in

A

bioavailability and increased side effects

30
Q

IV loading dose of amrinone

A

0.5-1.5mcg/kg

31
Q

after loading dose of amrinone how quickly does CO increase and last for

A

5 min to 2 hours persisting

32
Q

maintenance infusion of amrinone

A

2-10mcg/kg/min

33
Q

tachyphylaxis seen with amrinone?

A

no

34
Q

max daily dose of amrinone

A

10mg/kg including initial loading dose

35
Q

how often can you repeat a loading dose of amrinone

A

30 min after first injection

36
Q

how do we administer bolus dose of amrinone

A

slow due to hypotension

37
Q

who do we decrease amrinone dose for

A

renal dysfunction

38
Q

lab side effects form amrinone

A

dose related thrombocytompenai (espiecially with chronic PO therapy)
po accelerated platelet loss

39
Q

BP side effects of amrinone

A

hypotension from vasodilation

40
Q

amrinone and hypotension what can you give to help BP

A

vasopressors

41
Q

heart rate effects of amrinone

A

increases AV nodal conduction and decrease atrial refractoriness

42
Q

what is amrinone pro arrhythmic potential

A

does related and associated with IV administration.

43
Q

Bipyridine derivative of amrinone with almost 30 times the inotropic potency of amrinone but less adverse side effects. Thus replaced amrinone in clinical use

A

milrinone

44
Q

how does milrinone increase CO

A

CO improvement by increased inotropy as well as vascular smooth muscle relaxation of peripheral and pulmonary vessels.

45
Q
milrinone effects
LVEDP
MAP 
CVP, SVR 
Pulmonary Artery Occlusion Pressure
A
decreases
LVEDP
MAP
CVP, SVR
Pulmonary Artery Occlusion Pressure
46
Q

milrinone dose dependent increases in CI will do what to myocardial 02 consumption

A

Dose dependent increases in CI occur with minimal increases in myocardial O2 consumption.

47
Q

milrinone diastolic effects

A

improves diastolic function

48
Q

milrinone IV bolus

A

50mcg/kg

49
Q

milrinone iv maintenance

A

0.375 to 0.75 mcg/kg/min to maintain plasma concentrations at or above therapeutic levels.

50
Q

how fast do we give milrinone bolus

A

over 10 min

51
Q

milrinone max daily dose

A

1.3mg/kg/day

52
Q

how much milrinone is protein bound

A

70%

53
Q

how much milrinone is excreted unchanged by the kidenys

A

80%

54
Q

elimination half time of milrinone

A

2.7hrs

55
Q

what disease gets a decrease dose of milrinone

A

severe renal dysfunction

56
Q

how is milrinone used after cardiac surgery-2 ways

A

wean from cardiopulmonary bypass

management of acute LV dysfunction after cardiac surgery

57
Q

what can cause a reducted inotropic effect of milrinone

A

acidosis

58
Q

does milrinone cause tachycardia

A

rarely

59
Q

if patient has significant vasodilation or renal dysfunction which drug should they receive

A

dobutamine

60
Q

how does milrinone affect arterial grafts

A

reverses vasospasm

61
Q

which strange thing does milrinone have that may help after cardiopulmonary bpass

A

anti-inflammatory effects

62
Q

if patient has elevated PAP and needs continued beta blockade and increased risk for tacyarrhythmias what medication is most appropriate

A

milrinone

63
Q

milrinone may increase ____ in ischemic myocardium

A

ventricular automaticity

64
Q

what arrhythmias have been reported in milrinone

A

ventricular and supra ventricular arrhythmia

65
Q

what are milrinone effects on platelets

A

higher potency has less effects on platelets.
but short-term milrinone used does not cause significant changes in platelet number or function after cardiopulmonary bypass beyond the usual effects of cardiopulmonary bypass and cardiac surgery

66
Q

is milronone approved for HF

A

not FDA approved

67
Q

when might you see arrhythmias with milrinone

A

rapid IV loading dose

68
Q

what electrical change is the major electrophysiologic effect of milrinone

A

enhanced AV nodal conduction

69
Q

milronone with severe chronic heart failure is associated with

A

morbidity and mortality

70
Q

how do we mitigate hypotension with milrinone

A

slow bolus administration/give vasopressors