Antidysrhythmia drugs Flashcards Preview

semester 2 > Antidysrhythmia drugs > Flashcards

Flashcards in Antidysrhythmia drugs Deck (17):
1

Class 1 V-W

Sodium Channels, Lidocaine

2

Class 2 V-W

Beta Blockers, Atenolol

3

Class 3 V-W

Potassium channels, Amiodarone

4

Class 4 V-W

Calcium channels, Verapamil

5

Class 1 clinical

Supraventricular origin, adenosine, Verapamil

6

Class 2 clinical

Supraventricular or ventricular origin, Amiodarone, propranolol

7

Class 3 clinical

Ventricular origin, lidocaine

8

Class 4 clinical

Atrial fibrillation, atenolol (with sympathetic involvement), Amiodraone

9

Classification of Amiodarone

Clinical, class 2, and class 4
V-W, Class 3, but also classes 1 & 4

10

Effect of Amiodarone

Increases length of refactoryperiod by blocking K+ channels

11

Physiochemical properties of Amiodarone

Analogue of thyroid hormone, Very lipophilic, Large apparent volume of distribution, deposition of microcrystals in tissue, Months to reach stable plasma conc, 100 days for t1/2

12

Side effects of Amiodarone

Microcrystals in cornea -increased dazzle by light
Crystal in skin are photoxic
Hyperthyroidism
toxic to the liver
causes Bradycardia and conduction disruption

13

Classification of Adenosine

Class 1 clinical, unclassified
V-W

14

Action of Adenosine

Activates A1 Purinoceptors on cardiac myocytes, through a GPCR this opens K+ ach channels. this leads to inhibition of voltage sensitive calcium channels reducing action potential duration and reducing slope of pacemaker potential. This lowers the discharge rate of SA node reducing conduction and increasing refactory period of AV node

15

Uses of adenosine

suppresses Paroxysmal (occurs in attacks) supra ventricular tachycardia

16

Physiochemical properties of adenosine

naturally occurring purine nucleoside
effect lasts 30s
Plasma t1/2 is 10s
rapid uptake by erythrocytes and metabolism

17

side effects of adenosine

Severe bradycardia
Facial flushing
chest pain
Dyspnoea and Bronchospasm (should be avoided in asthma patients)