11.05 drugs/classes

Question 1

Quinidine

Answer 1

Class IA

• atrial arrhythmias, SVT
• moderate Na block Ph. 0; slow conduction; increases Action Potential Duration (APD)

Question 2

Procainamide

Answer 2

Class IA

• ventricular arrhythmias (NAPA: metabolite, has class II action)
• moderate Na block Ph. 0; slow conduction; increases Action Potential Duration (APD)

Question 3

Lidocaine

Answer 3

class IB

• VT, VF (old DOC), iv, im
• minimal Na block Ph 0; slow conduction (less): shorten ph 3 repolarization

Question 4

phenytoin

Answer 4

class IB

• Arrhythmia, oral anticonvulsant
• minimal Na block Ph 0; slow conduction (less): shorten ph 3 repolarization

Question 5

Flecainide

Answer 5

class IC

• for ventricular arrhythmia
• Marked Na block Ph.0; slow conduction; no change APD or repolarization. Increased suppression of Na channels

Question 6

Class IA

Answer 6

Quinidine, Procainamide, Disopyrimide

Moderate Na block Ph.0; slow conduction; incr. APD

Question 7

class IB

Answer 7

Lidocaine
Phenytoin
-Minimal Na block Ph.0; slow conduction (less);
shorten Ph.3 repolarization

Question 8

class IC

Answer 8

Flecainide
Encainide
-Marked Na block Ph.0; slow conduction; no change APD (action potential duration) or repolarization. Increased suppression of Na channels

Question 9

beta blockers for arrhythmic agents

Answer 9

-propranolol
-class II
decrease adrenergic input. No major effect on APD, suppress Ph.4 depolarization

Question 10

class II antiarrhythmics

Answer 10

beta blockers (ex propranolol)

Question 11

Amiodarone

Answer 11

• class III
• K channel blocker
• Prolong repolarization/refractory period other means than exclusively iNa block (mainly K+ channel blockade).

Question 12

Ibutilide

Answer 12

-class III
-K channel blocker
Prolong repolarization/refractory period other means than exclusively iNa block (mainly K+ channel blockade).

Question 13

class III antiarrhythmics, ex and mechanism

Answer 13

Amiodarone, Ibutilide

Prolong repolarization/refractory period other means than exclusively iNa block (mainly K+ channel blockade).

Question 14

class IV

Answer 14

Ca channel blockers (Verampamil, Diltiazem)
Slow conduction and increase effective refractory period in normal tissue (A-V node) and Ca-dependent slow responses of depolarized tissue (atria, ventricle, Purkinje)