Anti-disrhythmic drugs

Question 1

VWS

Class 1a

Answer 1

Dysopyramide

Procainamide

Question 2

VWS Class 1 what target?
What use?
Side effects

Answer 2

Blocks Na+ channels
Ventricular dysrhythmias
CNS: Suppression, convulsions

Question 3

VWS

Class 1b

Answer 3

Lidocaine

Question 4

VWS

Class 1c

Answer 4

Flecainide

Question 5

VWS 
Class 2 
Target
Uses
Unwanted effects

Answer 5

B1 adrenoceptor anatagonists
Supraventricular and ventricular dysrhytmias
Unwanted effects:
Cold extremities, bronchoconstriction, vivid dreams, hypoglycaemia, precipitation of cardiac failure/heart block

Question 6

VWS Class 2 drugs

Answer 6

propranolol

atenolol

Question 7

More detail as how class 2 drugs work

Answer 7

↑Discharge rate of SA Node
↑automaticity in ventricular and atrial myocardia
Improved conduction through AV node
Blocks B1 adrenoceptor in: SA node, AV node, ventricular tissue
Reduces phase 4 depolarisation of SA and AV node, therefore slows sinus rhythm and slows conduction through AV node

Question 8

Antidysrhytmic uses of B1-adrenoceptor antagonists

Answer 8

Suppression of dysrhymias induced by:

Excessive catecholamine release
Increased tissue sensitivity to catecholamines

Question 9

Amiodarone
Class
Mechanism
Properties

Answer 9

Class III - blocks K+ channels, prolongs AP
Also Class I and IV as also blocks Na+ and Ca2+

V.lipoholic
large volume of distribution
weeks/months of oral dosing before steady state plasma concentration is reached
Half life long, 10-100 days

Question 10

Amiodarone uses
Route of admin
Side effects

Answer 10

-atrial flutter or AF
-Paroxysmal supraventricular tachycardia (e.g. in Wolff-Parkinson-White syndrome)
-VF and ventricular tachycardia
Side effects:
-Microcrystals in cornea - increased dazzle from lights
-Photoxic reactions from microcrystals in skin - black and green skin - UV light reaction with microcrystal deposits
-Thyroidtoxicosis or hypothyroidism
-Diffuse pulmonary alveolitis, pneumonia
-Bradycardia and conduction disturbance

Question 11

Class IV drugs 
Mechanism of action
2 examples 
Uses
Adverse effects

Answer 11

Verapamil, Diltiazem
Calcium channel blockers/calcium antagonists
Uses: PSVT, can reduce ventricular rate in AF
Adverse effects:
-can make dysrhythmias worse, dangerous in ventricular dysrhythmias and WFW syndrome
-Hypotension
-cardiodepression
-oedma
-AV node block
-headache
-constipation