lecture 10 - calcium channel blockers Flashcards
What are the 2 types of selectivity of calcium channel blocker?
Vasoselective, Cardioselective
What is a common example of a vasoselective calcium channel blocker?
Amlodipine
What is an exampple of a cardioselective calcium channel blocker?
Diltiazem
What type of channel is antagonised by calcium channel blockers?
L-type calcium channels
Where are L-type calcium channels found?
In cardiac and vascular smooth muscle
What is the affect of vasoselective calcium channel blockers on blood vessels?
Prevent Ca2+ entry into vascular smooth muscle, causing vasodilation
What are the effects of cardioselective calcium channel blockers on the heart?
negative inotrope, negative chronotrope, negative dromotrope
What is the key indication for dihydropyridine/vasoselective calcium channel blockers?
hypertension
Which calcium channel blocker is indicated for arrhythmias?
Diltiazem
Which calcium channel blockers are indicated for angina?
Verapamil, diltiazem
What is a common example of a dihydropyridine/vasoselective calcium channel blocker?
Amlodipine
How does amlodipine have vasoselectivity?
It binds to inactivated L-type Ca2+ channels, which are more likely to exist in vascular smooth muscle because depolarisations are longer lasting
What are the contraindications for diltiazem?
heart failure, severe bradycardia
What drug class should not be used concurrently with calcium channel blockers?
Beta-Blockers
What are the primary action of nitrate dilators?
Venous dilation (also will be systemic arterial dilation)
What type of nitrodilator is administered via a sublingual spray?
Glyceryl trinitrate (GTN)
How do nitrates provide symptomatic relief for ischaemic chest pain?
They cause vasodilation in the veins, decreasing preload on the heart, and reduce systemic arterial resistance decreasing after-load which decreases the stress on the ventricles and therefore their O2 demand.
What are the indications for glyceryl trinitrate?
angina, MI, congestive heart failure
What are the adverse effects of nitrates?
flushing, headache, reflex tachycardia
