Pharm - Antiarrhythmics Flashcards

1
Q

What are the Vaughn Williams classes

A
IA
IB
IC
II
III
IV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

3 Class IA drugs

A
  • Disoyramide
  • Procainamide
  • Quinidine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

3 Class IB drugs

A
  • Lidocaine
  • Mexiletine
  • Phenytoin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

2 class IC drugs

A
  • Flecainide

- Propafenone

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

1 Class II drug

A

beta blockers

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

5 Class III drugs

A
  • Amiodarone
  • Dofetilide
  • Ibutilide
  • Sotalol
  • Dronedarone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

2 Class IV drugs

A
  • dihydropyridine calcium channel blockers

- non-dihydropyridine calcium channel blockers

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

Class IA MoA

A
  • Moderate Na+ channel - K+ to a lesser extent
  • slow conduction velocity
  • prolong refractoriness
  • decrease automatic property of na-dependent conduction tissue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Class IB MoA

A

Weak Na+ channel antagonists

  • decrease conduction velocity
  • decrease refractory period
  • decrease automaticity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Class IC MoA

A

Extremely potent Na+ channel blockers

  • greatly slows conduction velocity
  • decreases automaticity
  • no change to refractory period
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Class II MoA

A

beta blockers
- anti-adrenergic blockers (SA and AV nodes)

  • decrease conduction velocity
  • increase refractory period
  • decrease automaticity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Class III Moa

A

Block K+ channels

  • prolongs refractoriness in atrial and ventricular tissue
  • delays repolarization
  • no affect on conduction velocity or automaticity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Class IV MoA

A

Calcium channel blockers

  • slow conduction velocity
  • prolong refractory period
  • decrease automaticity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Disopyramide ADR

A
  • hypotension (serious)
  • cardiac failure (serious)
  • anticholinergic (dry mouth, urinary hesitation, constipation) most common
  • EKG changes (widen QT interval)
  • proarrhythmic action
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Lidocaine ADR

A
  • CNS toxicity (most common)
  • Cardiovascular toxicity
  • GI: n/v anorexia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Mexiletine ADR

A
  • GI: n/v heartburn, take with food
  • CNS
  • Cardiovascular: heart failure and hypotension
  • Dermatitis: face and trunk
  • Proarrhythmic action: avoid in lesser arrhythmias like asymptomatic PVC
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Flecainide ADR

A
  • Cardiac toxicity (pro arrhythmic, conduction abnormalities, hemodynamics like negative inotropic effects)
  • dizziness, blurred vision, HA, nausea
  • neurotoxicity (dizzy, visual changes, psychosis, hallucinations, seizures)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Flecainide

- conduction abnormalities

A
  • prolongs depolarization
  • slows conduction in AV node/His-Purkinji
  • prolonged PR interval (slows dronotropy)
  • increased QRS
  • first and second degree heart block
  • No effect on QT
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Felcainide: what is main downside to hemodynamic changes

A

decreased inotrope can cause or worsen heart failure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Propafenone ADR

A
  • GI – dysgusia, nausea: take with food
  • CNS
  • Cardiovascular: beta blocker effects (negative inotropic activity, bradycardia, slow AV conduction, prolong PR and QRS intervals etc.)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

List the 7 big ADR associated with beta blockers

A
  1. Exacerbation of heart failure
  2. Negative chronotropic effect
  3. beta blocker withdrawal
  4. increased airway resistance
  5. facilitation of hypoglycemia
  6. fatigue
  7. sexual dysfunction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

beta blocker ADR

- Exacerbation of heart failure

A
  • Exacerbate heart failure in pts in acute decompensated situation
  • Cause heart failure in pt with preexisting myocardial dysfunction with borderline compensation
  • These pts’ cardiac output depends on sympathetic drive which is taken away by β-blockers
23
Q

beta blocker ADR

- Negative chronotropic effects

A
  • slowing heart rate which can be problem with pts who have sick sinus syndrome
  • depressing conduction through AV node, potentially causing heart block. This is a problem in pts with complete or partial AV conduction problems
24
Q

beta blocker ADR

- β-blocker withdrawal

A
  • Receptor upregulation due to continued blocking, when stop β-blocker, now have too much response to circulating catecholamines stimulation
  • Acute withdraw: can lead to morbidity and mortality, I pts with known CAD, can exacerbate ischemic sx (precipitation of acute MI)
  • Gradual tapering off β-blocker should be considered
25
Q

beta blocker ADR

- Increased airway resistance

A

Nonselective β-blockers prevent bronchodilation (bronchial β2 receptors) → increased airway resistance in pt with bronchospasm dz

26
Q

beta blocker ADR

- Facilitation of hypoglycemia

A
  • Epinephrine increases glucose production, helps prevent hypoglycemia.
  • β-blocker can increase risk of hypoglycemia because blocks release of glycogen from the liver when glucose is needed.
  • Epinephrine induces early warning signs of neuroglycopenia
  • β-blocker can decrease the perception of hypoglycemia (except sweating)
27
Q

beta blocker ADR

- fatigue

A

β-blocker reduces hearts ability to respond to increased activity

28
Q

Sotalol ADR

A
  • Cardiovascular
  • Prolonged QT
  • Bradycardia
  • Torsades de Pointes
  • New ventricular arrhythmias
  • New/worse heart failure
  • Proarrhythmia
29
Q

Amiodarone ADR - list 7 main

A
  1. Pulmonary
  2. Thyroid
  3. Cardiac toxicity
  4. Hepatotoxicity/GI
  5. Ocular Chanes
  6. Skin reactions
  7. Neuro
30
Q

Amiodarone

- Pulmonary ADR

A
  • Related to cumulative dose
  • Chronic interstitial pneumonitis is most common
  • Also organizing pneumonia, ARDS, solitary pulmonary mass
  • Nonproductive cough and dyspnea in affected pts
  • Pleuritic pain, weight loss, fever, malaise
31
Q

Amiodarone

- Thyroid ADR

A
  • Hypothyroidism
  • Can occur anytime, not dose related
  • Hyperthyroidism
  • Occurs early and suddenly
  • Thyrotoxic sx
  • Type I: related to iodine load = lots of thyroid hormone produced
  • Type II: destruction of thyroid cells leads to release of thyroid hormone
32
Q

Amiodarone

- Cardiac toxicity ADR

A
  • Ca2+ channel blocking activity
  • Sinus bradycardia
  • AV nodal block
  • K+ channel blocking activity
  • Prolongation of QT interval and repolarization
  • Ventricular arrhythmias
  • Torsades de Pointes – more common with other factors that prolong QT interval
33
Q

Amiodarone

- GI/Hepatoxicity ADR

A
  • Jaundice or hepatitis
  • Test AST and ALT (2X elevation = stop drug)
  • GI: n/v/d, anorexia, constipation
34
Q

Amiodarone

- Ocular Changes ADR

A
  • Corneal microdeposits: “cat whiskers” on cornea, not usually a problem
  • Optic neuropathy: Big time problem – optic nerve injury = unilateral or bilateral visual loss/blindness
35
Q

Amiodarone

- skin change ADRs

A
  • Photosensitivity

- Blue-gray slate colored skin

36
Q

Amiodarone

- neuro ADR

A

Many forms: tremor, ataxia, peripheral neuropathy, paresthesias, sleep disturbance

37
Q

Dronedarone ADR

A
  • GI: abd pain, n/d, rash
  • Hepatic damage
  • CV: 2X heart failure risk with given to pt with mod-to-severe left ventricular systolic dysfunction who are recently decompensated
  • Pulmonary toxicity
  • Skin reactions (eczema, rash, photosensitivity)
  • Thyroid issues seen in amiodarone
38
Q

Ibutilide ADR

A
  • Cardiac toxicity (Hypotension, sinus-tachy, supraventricular tachycardia, sinus bradycardia, AV block, BBB)
  • Proarrhythmias
39
Q

Disopyramide drug interactions

A

Contraindicated with concurrent use of drugs that prolong QT interval (quinolone abx, etc.)

40
Q

Flecainide drug interactions

A

Contraindicated with ritonavir (HIV drug)

41
Q

Sotalol drug interactions

A

QT prolonging drugs (macrolides, Zofran, etc.) bc sotalol also prolongs QT interval

42
Q

Amiodarone drug interactions

A
  1. Digoxin
  2. Warfarin
  3. Statins, esp. simvastatin
  4. Azoles
  5. quinolone abx
  6. QT prolonging drugs
43
Q

Amiodarone and Digoxin

  • effect
  • action
A
  • Amiodarone can increase digoxin levels

- Decrease digoxin by 25-50% empirically

44
Q

Amiodarone and Warfarin

  • effect
  • action
A
  • Amiodarone can change Warfarin metabolism, increasing levels
  • Can increase INR to dangerous levels
  • Decrease warfarin by 25-50% empirically
  • Titrate to INR goal
45
Q

Dronedarone drug interactions

A

QT prolonging drugs

46
Q

Monitoring tests and frequency for pts on Amiodarone

A
  1. PFT/CXR – baseline and if sx
  2. Thyroid panel – baseline, q 3-6 mo
  3. Liver panel – baseline, q 3-6 mo
  4. Eye exam – baseline, q 12 mo
  5. Interacting drug plasma level (esp warfarin) – baseline, PRN (INR weekly first 3-4 weeks)
  6. Clinical evaluation – baseline, q 3 mo
47
Q

5 Agents that increase risk of Torsades de Pointes

A
  1. Disopyramide
  2. Sotalol
  3. Dofetilide
  4. Amiodarone
  5. Ibutilide
48
Q

Risks of proarrhythmias with antiarrhythmic drugs

A
  • Potential to cause premature ventricular contractions, induce/aggravate VT, torsades de pointes, V-fib, conduction disturbances, bradycardia
  • Risks vary according to type of arrhythmia being treated, presence of structural heart disease, QT interval, pre-existing conduction disturbances, sinus node dysfunction, patient age, heart failure, left and right ventricular function
49
Q

What pt is risk for induced arrhythmia due to antiarrhythmic drug highest

A

pt with depressed LV function

50
Q

What is most recognized form of drug proarrhythmias

A

torsades de pointes

51
Q

Class I and risk of proarrhythmias

A

risk is higher with structural heart dz, esp coronary heart disease and/or left ventricular dysfn

52
Q

Class II and risk of proarrhythmias

A

bradycardia is biggest risk (except Sotalol which has class III properties at higher doses)

53
Q

Class III and risk of proarrhythmias

A

prolong repolarization → torsades de pointes and ventricular tachycardia