Chapter 23- Pharm Of Cardiac Rhythm Flashcards
What is the general goal of class 1 anti-arrhythmias
Sodium channel blockers
What is the goal of class 2 anti-arrhythmias
Beta adrenergic receptor antagonists
What is the goal of class 3 anti-arrhythmics
K+ channel blockers
What is the goal of class 4 anti-arrhythmics
Calcium Channel blockers
How is quinine administered
Orally
What are the class 1A antiarrhythmics
Quididine, procainamide, disopyramide
What are some side effects of quinidine
SLE, headache, lightheadedness, diarrhea, cinchonism
What are some contraindications for quinidine
Myasthenia gravis, conduction defects, history of tornadoes de pointed or prolonged QT interval
What drug toxicity can quinidine induce
Digoxin toxicity
What is a major contraindication of procainamide use
SLE
What pretreatment should be considered when using procainamide
Cardiac glycoside
What is the drug of choice for life-threatening ventricular arrhythmias
Disopyramide
What drug impairs the antiarrhythmic activity of disopyramide
Rifampin
Who is disopyramide often prescribed to
Patients that cannot tolerate quinidine or procainamide
What anti-arrhythmic is best for post-MI
class 1B
What are the class 1B anti-arrhythmics
Lidocaine/mexiletine, phenytoin
What class 1B anti-arrhythmic can be used for status epilepticus
Lidocaine/mexiletine
What is the first sign of lidocaine toxicity in severely ill patients
Seizures
What can intramuscular injection of lidocaine cause large increases in the level of
Creatine kinase
What are some contraindications of phenytoin
Hydantoin hypersensitivity, SA node block, stokes-Adams syndrome
What are the class 1C anti-arrhythmics
Encainide, flecainide, miricizine, propafenone
What are some clinical uses for class 1C
Sustained ventricular tachycardia, paraoxysmal supraventricular tachycardia
What anti-arrhythmics are associated with excessive mortality and non-fatal cardiac arrest
Class 1C
What levels must be monitored with class 1C
Levels in patients with significant hepatic impairment
What class of antiarrhythmics are only approved for life-threatening situations
Class 1C
What are the class 3 anti-arrhythmics
Ibutilide, dofetilide, sotalol, bretylium, amiodarone, dronedarone
What is the clinical application of ibutilide
Conversation of atrial fibrillation or atrial flutter to normal sinus rhythm
What does the block of K+ channels caused by class 3 result in
Longer action potential plateau and prolonged repolarization
What are contraindications of ibutilide
History of polymorphic ventricular tachycardia (tostadas de pointes), pre-existing long QT syndrome
What must be monitored when ibutilide is administered
QT interval
How is dofetilide administered
Orally
What is a unique contraindication of dofetilide
Patients with creatinine clearance less than 20mL/min
Who is dofetilide use reserved to patients with
With highly symptomatic atrial fibrillation and/or atrial flutter
What is dofetilide excreted by
Kidney
What class 3 antiarrhythmic is also a class 1
Sotalol
Who sotalol most frequently used in
Patients that cannot tolerate amiodarone
Who must satalol be used with caution in
Patients with impaired renal function or DM
What antiarrhythmic is contraindicated in patients with asthma
Sotalol
What is a contraindication for bretylium use
Digitalis-induced arrhythmias
What class 3 can be used in patients with depressed ejection function
Dofetilide
What anti-arrhythmic can act as all classes
Amiodarone
What antiarrhythmic can cause HF, severe pulmonary toxicity, thyroid dysfunction, corneal microdeposits, blue-gray skin pigmentation and photosensitivity
Amiodarone
What side effect is most common at high doses of amiodarone
Pulmonary toxicity
What antiarrhythmic can cause gasping syndrome in neonates
Amiodarone
What drug can cause amiodarone increased elimination when co-administered
Cholestyramine
Why is dronedarone less lipophilic than amiodarone
Lacks iodine moieties
What anti-arrhythmic is contraindicated in pregnancy
Dronedarone
Who should dronedarone be used with caution in
Patients with systolic heart failure
What anti-arrhythmic increases creatinine without affecting glomerular filtration rate
Dronedarone
What are common side effects of adenosine use
Facial flushing, bronchoconstriction in patients with asthma, headache, hypotension
What anti-arrhythmic opens G protein coupled K+ channels and suppresses Ca++ dependent action potential, thereby inhibiting SA nodal, atrial and AV nodal conduction
Adenosine
What may occur at onset of adenosine infusion
Transient arrhythmia
What anti-arrhythmic is notably less effective when used with caffeine
Adenosine
What is the clinical use of ranolazine
Chronic angina pectoris
What antiarrhythmic improves exercise capacity and reduces anginal events; inhibits fatty acid beta oxidation
Ranolazine
What are some common side effects of ranolazine
Constipation, dizziness, headache
On what phase(s) of the cardiac AP do amiodarone and sotalol wrk
Phase 0 and 3
On what phase(s) of the cardiac AP do lidocaine, flecainide, and quinidine work
Phase 0
On what phase(s) of the cardiac AP do beta blockers work
Phase 2 and 4
What is responsible for depolarization of SA and AV nodal fibers
Calcium ion (inward)
What ion current is responsible for the repolarization of SA and AV nodal fibers
Potassium ion (outward)
Where is the SA node located
Right atrium
What class of antiarrhythmic agents has membrane stabilizing effects
Beta-blockers
What is the general mechanism of class 1
Sodium channel blockers
What is the general mechanism of class 2
Beta blockers
What is the general mechanism of class 3
Potassium channel blockers
What is the mechanism of class 4
Calcium channel blockers
Magnesium is used to treat what specific type of arrhythmia
Torsades de pointes
What 2 drugs can antagonize the effects of adenosine
Theophylline and caffeine
What is the only subgroup of class1 that increase Ap duration and ERP
Class 1A
Drugs that affect AV conduction velocity are referred to as what types of agents
Dromotropes
What class 1a antiarrhythmic can cause peripheral vasoconstriction
Disopyramide
What class 1B antiarrhythmic can cause pulmonary fibrosis
Tocainide
Verapamil should not be given in what types of arrhythmias
Wolff-Parkinson’s-white (WPW) syndrome; ventricular tachycardia
Digoxin-induced arrhythmias are treated by what drugs
Lidocaine; phenytoin
