Cardiac Pharmacology Flashcards
Sodium Channel blockers - class I antiarrhythmics
1A - moderate Na channel bllockade, increased ERP
1B - weak Na channel blockage, reduced ERP
1C - strong Na channel blockage, extend ERP
cardiac effects of beta adrenoceptor antagonists (beta blockers)
decreased contractility
decrease relaxation
decrease heart rate
decrease conduction velocity
vascular effects of beta blockers
smooth muscle contraction
use of beta blockers for:
hypertension angina myocardial infarction arrhythmias heart failure
potassium channel blockers - class III
delayed repolarisation by potassium channel blockage
calcium channel blockers - class IV cardiac effects
decrease contractility
decrease heart rate
decrease conduction velocity
vascular effects of calcium channel blockers
smooth muscle relaxant
therapeutic use of calcium channel blockers
hypertension
angina
arrhythmias
cardiac glycosides MOA
digitalis compounds are potent inhibitors of cellular NaK ATPase
this ion transport system moves sodium ions out of the cell and brings potassium ions into the cell
Uses of digitalis compounds
heart failure - increase inotropy, increase ejection fraction, reduce preload
arrhythmias - vasodilators, cardiac depressants
atropine
the vagus nerves that innervate the heart release ACh as their primary neurotransmitter. ACh binds to muscarinic receptors that are found on cells compromising the SA and AV nodes
why use antianginal drugs?
increase oxygen delivery - coronary vasodilators, anti-thrombotic drugs
decrease oxygen demand - vasodilators, cardiac depressants
classes of drugs used to treat angina
vasodilators
cardioinhibitory drugs
anti-thrombotic drugs
Loop diuretics
inhibit sodium potassium chloride cotransporter in the thick ascending limb
therefore leads to increase in distal tubular concentration of sodium, reduced hypertonicity of the surrounding interstitium and less water reabsorption in the collecting duct
thiazine diuretics
inhibit sodium chloride transporter in the distal tubule
