Antidysrhythmic Drug Part II Flashcards
What drug class does Amiodarone belong?
(Class III)
What is the characteristics of Amiodarone (Class III)?
Potent antiarrhythmic with wide spectrum of activity against refractory supraventricular and ventricular tachyarrhythmias
What is Amiodarone (Class III) effective in treating?
- Effective in tx WPW, decreases risk of Afib after cardiac surgery
- Tx of VT/VF resistant to defibrillation (in ACLS protocol)
What can Amiodarone (Class III) decrease?
Decreases mortality after MI
What is the MOA of Amiodarone (Class III)?
- Prolongs the ERP in all cardiac tissue (SA & AV node, atrium, His-Purkinje system, ventricles & accessory bypass tracts [WPW])
- Antiadrenergic effects (noncompetitive alpha and beta receptor blockade)
- Antianginal (dilates coronary arteries/increases coronary blood flow)
What is the cause of pulmonary toxicity associated with Amiodarone (Class III)?
poss R/T production of free oxygen radicals in the lungs
What can pulmonary toxicity with Amiodarone (Class III) lead to?
Can lead to ARDS, pulmonary edema
What effect can High FiO2 have on pulmonary toxicity of Amiodarone (Class III)?
High FiO2 may accelerate free oxygen radical damage to lung tissue
What effect can lower FiO2 have from pulmonary toxicity of Amiodarone (Class III)?
Lower FiO2 to lowest level capable of maintaining adequate systemic oxygenation
What is the side effects of Amiodarone-induced pulmonary toxicity?
dyspnea, cough, pulmonary infiltrates on CXR, hypoxemia
What are the CV effects of Amiodarone (Class III)?
- Prolong QTc interval on ECG
- proarrhythmic effect (incr. risk of torsades)
- slow HR resistant to atropine
- decreased responsiveness to sympathomimetics since it blocks these receptors
How is hypotension occurs from Amiodarone (Class III)?
Hypotension d/t peripheral vasodilating effect: (tx w/vasopressin)
What can enhance the negative inotropic effects of Amiodarone (Class III)?
Negative inotropic effects enhanced w/admin of GA, β-blockers, CCBs
What are some other side effevts associated with Amiodarone (Class III)?
- Optic neuropathy
- photosensitivity
- rash
- cyanotic discoloration of face
- neurologic toxicity (peripheral neuropathy, tremors)
What is the half life of Amiodarone (Class III)?
Long elimination half-time (29 days)
What is the volume of Vd of Amiodarone (Class III)?
large Vd
What is the protein binding of Amiodarone (Class III)?
Extensive tissue protein binding
What is the active metabolite for Amiodarone (Class III)?
longer elim half-time than parent drug leads to accumulation of metabolite w/chronic therapy
What medications can effect Amiodarone (Class III) drug levels?
Inhibits P450 enzymes so can increase drug levels: digoxin, procainamide, quinidine, warfarin, cyclosporine, quinidine, procainamide, phenytoin
What is true about digoxin and Amiodarone (Class III)?
Displaces digoxin from protein binding sites (digoxin dose should be by 50%)
What does Amiodarone (Class III) contain?
Amiodarone contains iodine; has effects on thyroid function (hyper or hypothyroidism)
What are the drug classes of Sotalol?
(Class III)
What is the properties of Sotalol (Class III)?
Nonselective β-adrenergic antagonist at low doses, higher doses prolongs cardiac AP in atria, ventricles and accessory tracts
What effect can be seen with Sotalol (Class III)?
β blockade effects: decreased contractility, bradycardia, delayed AV
What is the clinical uses of Sotalol (Class III)?
Treatment of sustained VT/VF, a-tachycardia, & afib
When should Sotalol (Class III) be avoided?
Avoid in asthmatics, LV dysfunction, conduction abnormalities such as prolonged QTc interval on ECG
When is Sotalol (Class III) used?
Proarrhythmic; use saved for life threatening ventricular arrhythmias
What is the excretion of Sotalol (Class III)? When is this a concern?
Excreted by kidneys, concerns with renal dysfunction
What is the metabolism of Sotalol (Class III)?
not metabolized
What is the most serious effect of Sotalol (Class III)?
side effect is Torsades de pointes that is dose related (prolongs the QTc)
What are the drug class of Ibutilide/Dofetilide?
(Class III)
What is the use of Ibutilide?
recent onset of Afib/Aflutter
What is a property of Ibutilide?
Polymorphic VT with +/- QT prolongation that can be problematic with those with predisposing factors