Drug for Heart Failure
Review: 【Pharmacology】Heart Failure
Content:
2. Angiotensin-converting enzyme (ACE) inhibitors
3. Angiotensin receptor blockers (ARBs)
4. Angiotensin receptor-neprilysin inhibitor
5. Aldosterone antagonists
6. Loop diuretics
7. Vasodilators
8. Digoxin
9. Reference
1. Beta-blockers
work by binding to beta-1 receptors in the heart
- blocking the action of norepinephrine
- reducing heart rate and contractility
- decreases cardiac output and blood pressure
*Decreased heart rate allows more diastolic filling time, so the stroke volume is typically not reduced.
via blockade of the alpha 1 receptors of the renal juxtaglomerular complex,
- certain beta-blockers may also reduce renin secretion
- reducing the severity of angiotensin II-induced vasoconstriction & aldosterone-induced volume expansion
***however is not beta-blockers primary mechanism of action.
Review:【Pharmacology】Adrenergic drug (adrenergic antagonists)
Currently only three have proven to reduce mortality in heart failure patients
Drug:
- Bisoprolol
- Carvedilol
- Carvedilol blocks
- beta-1 receptors in the heart
- alpha-1 receptors located on the smooth muscles of arteries and veins.
- By preventing norepinephrine from activating the alpha-1 receptor,
- Carvedilol causes vessels to dilate
- reducing total peripheral resistance
- Metoprolol
2. Angiotensin-converting enzyme (ACE) inhibitors
- selectively inhibit the angiotensin-converting enzyme
- reduces angiotensin II production
- reduce its effects on vasoconstriction as well as ADH and aldosterone secretion.
- increases levels of a potent vasoactive peptide called bradykinin.
- Angiotensin II: vasoconstrictor
- bradykinin: endogenous vasodilator, degraded by ACE
- When ACE inhibition occurs,
- Angiotensin II levels drop
- bradykinin levels rise.
- blood vessels become dilated
- total peripheral resistance is reduced
- blood pressure is lowered
- reducing the effort needed to pump blood around the body.
Drugs:
- Captopril
- Enalapril
- Fosinopril
- Lisinopril
- Quinapril
- Ramipril
3. Angiotensin receptor blockers (ARBs)
- works on the same angiotensin pathway
- However instead of blocking the enzyme that drives angiotensin II production,
- ARBs work by binding to AT1 receptors located on vascular smooth muscle & other tissues such as heart
- directly blocking the actions of angiotensin II.
- effects are similar to ACE inhibitors that is
- less vasoconstriction and less ADH and aldosterone secretion
- lowers blood pressure
- prevents damage to the heart and kidneys
- because ARBs do not inhibit ACE, they do not cause bradykinin levels to rise.
- bradykinin not only contributes to the vasodilation but also contributes to some of the side effects of ACE inhibitors
- such as cough and angioedema.
- Candesartan
- Losartan
- Telmisartan
- Valsartan
4. Angiotensin receptor-neprilysin inhibitor
- circulating enzyme that degrades several endogenous vasoactive peptides, including
- ANP
- BNP
- CNP
- terminates their positive actions.
- combines angiotensin receptor blocker and neprilysin inhibitor
- simultaneously block angiotensin II receptor & inhibit neprilysin enzyme
- preventing it from breaking down natriuretic peptides.
- increased longevity of natriuretic peptides
- enhancement of their beneficial effects.
5. Aldosterone antagonists
- work by competitively blocking the binding of aldosterone to the mineralocorticoid receptor
- decreasing the reabsorption of sodium and water
- decreasing the excretion of potassium
- leading to cardioprotective effects.
- also refer to this class of drugs as Potassium-sparing diuretics.
- Eplerenone
- Spironolactone
6. Loop diuretics
- by inhibiting the luminal sodium-potassium-chloride cotransporter located in the thick ascending limb of the loop of Henle
- about 20% to 30% of the filtered sodium is managed.
- reduce reabsorption of a much greater proportion of sodium.
- Sodium excreted along with the water
- significant decrease in
- plasma volume
- cardiac workload
- oxygen demand
- thus relieving signs and symptoms of volume excess
- Bumetanide
- Furosemide
- Torsemide
7. Vasodilators
- Isosorbide dinitrate
- releases nitric oxide (NO) in the vascular smooth muscle cell
- activates guanylyl cyclase (GC)
- an enzyme that catalyzes the formation of cyclic guanosine monophosphate (cGMP) from guanosine triphosphate (GTP).
- Increased intracellular cGMP activates a series of reactions
- cause decrease in intracellular calcium concentrations.
- leads to smooth muscle relaxation and thus vasodilation.
- Hydralazine
- appears to have multiple effects on the vascular smooth muscle, which include
- stimulation of nitric oxide release from the vascular endothelium
- stimulating cGMP production
- decreasing calcium concentration
- opening of potassium channels
- inhibition of calcium release from the sarcoplasmic reticulum
- altogether contribute to smooth muscle relaxation and subsequent vasodilation.
8. Digoxin
- by inhibiting the sodium potassium ATPase pump in cardiac muscle cells
- which is responsible for moving sodium ions out of the cell and bringing potassium ions into the cell.
- This inhibition cause when sodium concentration in the cardiac cell increases,
- sodium-calcium exchanger pushes the excess sodium ions out while bringing additional calcium ions in.
- causes an increase in the intracellular calcium
- available to the contractile proteins.
- increased force of contraction and thus increased cardiac output
9. Reference
https://youtu.be/AJV1BsRnImA
Related Link: 【Pharmacology】Arrhythmic 【Pharmacology】Antiarrhythmic
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