Diuretics and Inotropic Agents in Heart Failure

Flashcards covering the pharmacology of heart failure, including diuretics, inotropes, vasodilators, and clinical monitoring requirements based on the lecture transcript.

Peripheral Oedema

A condition where fluid leaks into the peripheral tissues as a result of increased pressure in the vasculature during heart failure.

Pulmonary Oedema

A condition occurring when fluid leaks into the lungs due to improper heart filling and increased vascular pressure.

Universal Mechanism (Diuretics)

Reduction of fluid retention by targeting the kidneys to increase the excretion of sodium ions ($Na^+$), which reduces total blood volume and preload.

Aldosterone Antagonists

A drug class including Spironolactone and Adlerinone that reduces aldosterone-induced myocardial vascular damage.

Spironolactone

An aldosterone antagonist that binds to the mineralocorticoid receptor and inhibits the expression of the $Na^+$ channel and the $Na^+/K^+ \text{ ATPase}$ pump at the collecting duct.

Frisamine (furosemide)

The most potent loop diuretic available, used for symptomatic relief to provide morbidity benefits rather than mortality benefits.

Mechanism of Action (Loop Diuretics)

Inhibition of the sodium-potassium-dichloride symporter ($Na^+/K^+/2Cl^-$) at the luminal membrane of the ascending loop of HETLINE.

Furosemide Renal Dosing Exception

A unique dosing strategy where the dose must be increased in renally impaired patients because the drug depends on reaching the tubular lumen via the filtrate to block the symporter.

Digoxin (Clinical Use in Heart Failure)

Used as a positive inotropic agent to increase cardiac contractility, unlike its use in Arrhythmia to decrease heart rate.

Mechanism of Action (Digoxin)

Inhibition of the $Na^+/K^+ \text{ ATPase}$ pump on the cardiac membrane, preventing sodium efflux and trapping more calcium ($Ca^{2+}$) ions inside myocytes to increase contractility.

Therapeutic Index (Digoxin)

Described as very narrow, necessitating Therapeutic Drug Monitoring (TDM) to avoid toxicity.

Adverse Effects of Digoxin

High risk of toxicity including symptoms such as nausea, vomiting, blurred vision, confusion, and bradycardia.

Mirinone

An agent that inhibits the breakdown of cyclic AMP ($cAMP$), leading to increased cardiac contractility without increasing myocardial oxygen demand.

Dobutamine

A $\beta_1$ agonist and sympathomimetic used to increase cardiac contractility.

Avobradin

A medication used in the management of heart failure that acts as a reducer of heart rate.

Nitrates

Vasodilators used in heart failure management to reduce preload.

Hydralazine

A vasodilator used in heart failure management to reduce afterload.

SAGL2 inhibitors (SGLT2 inhibitors)

A new addition to the established classes of heart failure pharmacotherapy.

Weight Monitoring

A daily clinical monitoring task for heart failure patients to detect fluid overload rather than tracking body fat.

Deep stare (dyspnea)

A consequence of non-compliance with salt or fluid restrictions in heart failure patients.