2007A08 List the classes of drugs used clinically to treat chronic left ventricular failure. Outline their mechanisms of action.

Group

Example

Mechanism

Beta blocker

Metoprolol

β₁ antagonist. ↓G_s G protein coupled receptor -> ↓ adenyly cyclase -> ↓cAMP

↓SNS overdrive -> ↓remodelling

↓Renin release -> ↓Angiotensin 2 -> ↓remodelling, ↓ intravascular volume, ↓SVR

ACE inhibitor

Perindopril

↓Angiotensin 2, ↑bradykinin, ↑natriuretic peptides

↓Remodelling

↓Na⁺/H₂O retention

ARB

Irbesartan

(Like ACEi but no effect on bradykinin/natriuretic peptides)

Neprilysin inhibitor

Saccubitril

↑Bradykinin, natriuretic peptides

↓Na⁺, H₂O retention

↓Remodelling

Diuretic

Spironolactone

↓Na⁺, H₂O retention

Cardiac glycoside

Digoxin

Inhibit Na⁺K⁺ATPase. ↑ICF [Ca²⁺]