Heart Failure Pharmacology Flashcards
Goal of CHF Pharmacology
Treating the maladaptations of the heart (inappropriate response of the heart)
Most relevant drugs in CHF management
ACE Inhibitor and Beta blockers
Patients with oedema should receive a diuretic
Example of an ACE Inhibitor
Ramipril (Remember the suffix ‘pril’)
Role of ACE Inhibitors (ACEIs)
Reducing afterload and preload
Reducing salt/water rention to a degree as it interacts with the aldosterone side of things
Most importantly inhibits RAAS which prevents cardiac remodelling
How to use ACEIs
Low dose then titrate up
Monitor eGFR and K+ before and during treatment
(ACEIs increase plasma K+)
Effect of Aldosterone on Sodium and Potassium
Aldosterone is a sodium retaining and potassium losing hormone
Risk of ACEIs in terms of BP (and treatment of side effect)
ACEIs may cause severe hypotension. If this is a risk, withdraw diuretic therapy for a few days before and give ACEIs at night to prevent falling
What does a small drop in eGFR indicate when ACEI therapy begins
It indicates that they are doing their job
Respiratory side effect of ACEIs and why (vaguely)
Occasionally a dry cough at the start of therapy that tends to be quite managable
Because ACE also breaks down bradykinin
Important contraindication of ACEIs and why
Renovascular disease
Let’s say we have atherosclerosis in renal artery; Kidney releases a lot of renin to compensate and so the body’s BP becomes reliant on RAAS
ACEIs affect this system and can cause significant hypotension
AT1 Receptor antagonists
aka ATRAs or ARBs
Block actions of Angiotensin II at AT1 Receptors; alternative to ACEIs in CHF but far less likely to give cough
Example of AT1 Receptor Antagonist
Losartan (Suffix -sartan)
Beta blockers on CHF
It can precipitate heart failure
Although, if used in very low doses to start with, they are first line along with ACEIs
They are anti-arrythmics
Key is that they take out the toxicity of the sympathetic nervous system that causes myocyte dysfunction
Are B blockers contraindicated in COPD
No; COPD is no reason to avoid beta blockers
Dosage of beta blockers on CHF patients at beginning
Begin with tiny dose of bisoprolol due to negative ionotropic and chronotropic effects of beta blockers (symptoms may initially get worse after initiating treatment and that’s ok)
Mechanism of digoxin
Positive inotrope;
Inhibits Na+/K+ ATPase so that Na+ accumulates in myocytes to be exchanged with Ca2+ which leads to increased contractility
