antidysrhythmic drugs

Question 1

what are antidysrhythmic drugs

Answer 1

medications used to treat abnormal heart rhythms (dysrhythmias or arrhythmias). they modify electrical impulses in the heart aiming to restore normal rhythm or control the heart rate

Question 2

what are class 1 antidysrhythmic drugs

Answer 2

sodium channel blockers
block sodium channels slowing depolarisation in cardiac myocytes

Question 3

what are the sub types of class 1 antidysrhythmics

Answer 3

class 1a
class 1b
class 1c

Question 4

what do class 1a drugs do

Answer 4

moderate sodium channel blockade prolongs action potential duration
examples quinidine, procainamide, disopyramide

Question 5

example of class 1a drugs

Answer 5

quinidine
procainamide
disopyramide

Question 6

what indications are class 1a drugs used to treat

Answer 6

atrial fibrilation
ventricular tachychardia

Question 7

what are class 1b drugs used for

Answer 7

mild sodium channel blockade, shortens action potential duration

Question 8

what are examples of class 1b drugs

Answer 8

lidocaine
mexiletine

Question 9

what indications are class 1b drugs used for

Answer 9

ventricular arrythmias, post myocardial infarction

Question 10

what are class 1c drugs used for

Answer 10

strong sodium channel blockade little affect on action potential duration

Question 11

examples of class 1 drugs

Answer 11

flecainide,propafenone

Question 12

what indications are class 1 drugs used for

Answer 12

life threatening ventricular arrythmias, atrial fibrilation

Question 13

what are class ii antidysrhythmic drugs

Answer 13

beta blockers

Question 14

what are the mechanisms of beta blockers

Answer 14

increase perfusion time and so diastolic time (which means coronary blood flow is increased)
block beta adrenergic receptors, reducing heart rate and contractility decreasing sympathetic stimulation

Question 15

what are examples of beta blockers

Answer 15

propranolol, metorprolol,esmolol

Question 16

what indications can beta blockers such as esmolol, proranolol and metorprolol be used to treat

Answer 16

atrial fibrilation, atrial flutter, ventricular arrythmias, arrythmias triggered by stress or exercise

Question 17

what mechanism do class iii potassium channel blockers workby

Answer 17

prolong repolarisation by inhibiting potassium efflux during phase 3 of the action potential

Question 18

what are examples of class iii anti dysarrythmic drugs (potassium channel blockers)

Answer 18

amiodarone,sotalol,dofetilide,ibutilide

Question 19

what are indications of class iii potassium ion channel blockers

Answer 19

atrial fibrilation, atrial flutter, ventricular tachychardia

Question 20

what is special about amiodarone

Answer 20

has effects across multiple classes and requires monitoring for long term toxicities

Question 21

how do class 4 calcium ion channel blockers work

Answer 21

block l type calcium channels, slowing conduction through av node

Question 22

what are examples of calcium ion channel blockers

Answer 22

verapamil,dilitiazem

Question 23

what indications are calcium ion channel blockers used to treat

Answer 23

supraventricular tachychardia, atrial fibrilation,atrial flutter

Question 24

what kind of patients are class 4 channel drugs avoided in

Answer 24

patients with heart failure and reduced ejection fraction

Question 25

what are class five drugs, miscellaneous

Answer 25

includes drugs that do not fit into any category but has antidysrhythmic effects

Question 26

what are examples of class five drugs

Answer 26

adenosine-short acting, slows conduction through the av node digoxin- increases vagal tone slowing av conduction

Question 27

explain mechanism of miscallaenous drug digoxin

Answer 27

increases vagal tone slowing av conduction indications-atrial fibrilation atrial flutter

Question 28

explain mechanism of miscallaenous drug adenosine

Answer 28

short acting slows conduction through av node indications acute termination of superaventricular tachychardia

Question 29

how does magnesium sulfate cause anti dysrhythmic effects

Answer 29

stabilises myocardial cells

Question 30

what considerations are taken into account for antidysrythmic therapy

Answer 30

patient specific factors adverse effects drug interactions monitoring

Question 31

what patient specific factors are considered in antidysrythmic therapy

Answer 31

type of arrythmia (atrial vs ventricular) underlying conditions (heart failure, ischeamic heart disease) renal and hepatic functionfor drug metabolism and clearance

Question 32

what adverse effects can occur

Answer 32

proarrythmia- can induce arrythmias some drugs non cardiac toxcities amiodarone, thyroid dysfunction, pulmonary fibrosis,liver toxicity beta blockers- fatigue, bronchospasm, bradychardia calcium channel blockers-peripheral edema, constipation

Question 33

what kind of monitoring is needed

Answer 33

regular ecgs to access effectiveness and watch for adverse effects lab tests for drug levels and side effects (thyroid, liver function with amiodarone)

Question 34

where is lidocaine inserted

Answer 34

intracardiac because if given intravenously, the injection would get stuck there