Pharmacology: anti-arrythmics Class 1

Question 1

describe the action of class 1 anti-arrythmics

Answer 1

Na channel blockers- block phase 0 in the ventricles

Question 2

when do class 1 anti-arrythmics associate with Na channels

Answer 2

when they are open/inactive

Question 3

when do class 1 anti-arrthymics dissociate with Na channels

Answer 3

when they are in their resting state

Question 4

how are class 1 anti-arrythmics subclassified

Answer 4

by how quickly they associate/dissociate with the Na channel

Question 5

give an example of a class 1a anti-arrythmic and the speed of dissociation/association

Answer 5

disopyramide

moderate

Question 6

give an example of a class 1b anti-arrythmic and the speed of dissociation/association

Answer 6

lignocaine

rapid

Question 7

give an example of a class 1c anti-arrythmic and the speed of dissociation/association

Answer 7

flecainide

slow

Question 8

describe the action of class 1a drugs

Answer 8

slow rate of action potential rise and prolong refractory period

Question 9

describe the action of class 1b drugs

Answer 9

prevent premature beats

Question 10

describe action of class 1c drugs

Answer 10

depress conduction