Cardiac theraputics

Question 1

Cardiac Drugs list:

Answer 1

Loop Diuretics
Thiazide diuretics
Potassium sparing diuretics
Beta blockers
Calcium antagonists
ACE inhibitors
AT1 blockers
Nitrates

Cardiac Glycosides
Anti-dysrhythmics
Anti-platelet agents
Thrombolytics

Heparins
Oral anticoagulants
Novel anticoagulants
Statins

Question 2

What is a loop diuretic?

Answer 2

Loop diuretics are medicines that make the kidneys pass out more fluid and ease symptoms of heart failure and other conditions.

Question 3

How does a loop diuretic work?

Answer 3

1. Acts principally on the ascending loop of Henle, where they inhibit the Na+/K+/2Cl- co-transporter.
2. This protein is responsible for transporting sodium, potassium and chloride ions
   from the tubular lumen into the epithelial cell. Water then follows by osmosis.
3. Inhibiting this
   process has a potent diuretic effect.

Question 4

How do loop diuretics help acute heart failure patients?

Answer 4

1. Loop diuretics have a direct effect on blood vessels, causing dilatation of capacitance veins.
2. This reduces preload and improves the contractile function of the ‘overstretched’ heart muscle.
3. This is the main benefit of loop diuretics in acute heart failure as the clinical response is usually evident before a diuresis is established.

Question 5

What are the 3 main indications for use of loop diuretics?

Answer 5

1. For relief of breathlessness in acute pulmonary oedema in conjunction with oxygen and nitrates.
2. For symptomatic treatment of fluid overload in chronic heart failure.
3. For symptomatic treatment of fluid overload in other oedematous states, e.g. due to renal disease or liver failure, where they may be given in combination with other
   diuretics

Question 6

What are the 4 main contraindications of loop diuretics?

Answer 6

1. Severe hypovolemia or dehydration
2. Used with caution in patients with risk of hepatic encephalopathy
3. Severe hypokalaemia or hyponatraemia.
4. Taken chronically, loop diuretics inhibit uric acid excretion and this can worsen gout.

Question 7

What are the main side-effects of loop diuretics?

Answer 7

1. Dehydration and hypotension
2. Almost any low electrolyte state
3. Hearing loss and tinnitus

Question 8

What are the 3 main possible negative interations of loop diuretics?

Answer 8

1. Lithium levels are increased due to reduced excretion
2. Risk of digoxin toxicity because of diuretic-associated hypokalaemia.
3. Loop diuretics can increase the ototoxicity and nephrotoxicity of aminoglycosides

Question 9

Name 3 loop diuretics?

Answer 9

1. Furosemide
2. Bumetanide
3. Torsemide

Question 10

What two classes of thiazide diuretics are there?

Answer 10

1. Thiazide diuretics
2. Thiazide like diuretics

Question 11

How do thiazide diuretics work?

Answer 11

1. Thiazides inhibit the Na+
   /Cl- co-transporter in the distal convoluted tubule of the
   nephron. This prevents the reabsorption of sodium and its osmotically associated water
2. The resulting diuresis causes an initial fall in extracellular fluid volume.
3. Over time, compensatory
   changes (e.g. Activation of the renin-angiotensin system) tend to reverse this, at least in part.
4. The long term antihypertensive effect is probably mediated by vasodilation, the mechanism of
   which is incompletely understood.

Question 12

What are the 2 main indications of thiazides?

Answer 12

1. Thiazides are an alternative first-line treatment for hypertension where a calcium channel blocker would otherwise be used but is either unsuitable (e.g. Due to Oedema) or there are features of heart failure.
2. Thiazides are also add-ons for the treatment of hypertension in patients whose blood
   pressure is not adequately controlled by a calcium channel blocker plus an ACE inhibitor
   or angiotensin receptor blocker (ARB).

Question 13

What are the 2 main contraindications for thiazides?

Answer 13

1. Hypokalaemia and hyponatraemia
2. Patients with gout

Question 14

What are the main side effects of thiazides?

Answer 14

1. Hyponatraemia and hypokalaemia
2. Cardiac arrhythmias
3. Impotence in men

Question 15

What are the 2 main possible interactions for thiazides?

Answer 15

1. The effectiveness of thiazides may be reduced by non-steroidal anti-inflammatory drugs
2. The combination of thiazides with other drugs that
   lower the serum potassium concentration (e.g. loop diuretics) is best avoided. If combination is
   essential, it should prompt intensive electrolyte monitoring.

Question 16

What is aldosterone?

Answer 16

Aldosterone is a mineralocorticoid that is produced in the adrenal cortex. It acts on
mineralocorticoid receptors in the distal tubules of the kidneys to increase the activity of
luminal epithelial sodium channels (ENaC). This increases the reabsorption of sodium and water
(which elevates blood pressure) with the by-product of increased potassium excretion

Question 17

How do K-Sparing diuretics/Aldosterone antagonist diuretics work?

Answer 17

Aldosterone antagonists inhibit the effect of aldosterone by binding competitively to the
aldosterone receptor. This increases sodium and water excretion and potassium retention. Their
effect is greatest in primary hyperaldosteronism or when circulating aldosterone is released,
e.g. In cirrhosis.

Question 18

What are the 3 main indications for K-Sparing diuretics/Aldosterone antagonist diuretics?

Answer 18

1. Ascites and oedema due to liver cirrhosis - spironolactone is the first line
2. Chronic heart failure: of at least moderate severity or arising within 1 month of an MI,
   usually in addition to a beta-blocker and an ACE inhibitor/angiotensin receptor blocker
3. Primary hyperaldosteronism: For patients awaiting surgery or for whom surgery is not
   an option

Question 19

What are the 4 main contraindications for K-Sparing diuretics/Aldosterone antagonist diuretics?

Answer 19

1. Severe renal impairment
2. Hyperkalaemia
3. Addison’s disease
4. Pregnant or lactating women.

Question 20

What are 4 main side effects of K-Sparing diuretics/Aldosterone antagonist diuretics?

Answer 20

1. Hyperkalaemia (Can lead to muscle weakness, arrhythmias and cardiac arrest)
2. Gynaecomastia
3. Liver impairment and jaundice
4. Stevens-Johnsons syndrome

Question 21

Name 3 thiazides?

Answer 21

Chlortalidone
Indapamide
Bendroflumethiazide

Question 22

Name 3 Cardiovascular
K-Sparing diuretics/Aldosterone antagonist diuretics?

Answer 22

1. Spironolactone
2. Eplerenone
3. Finerenone

Question 23

What is an ACE-inhibitor?

Answer 23

An ACE inhibitor is a type of medication that lowers blood pressure by relaxing the veins and arteries

Question 24

How does an ACE-inhibitor work?

Answer 24

1. ACE inhibitors block the action of angiotensin-converting enzyme to prevent the conversion of
   angiotensin I to angiotensin II
2. . Angiotensin II is a vasoconstrictor and stimulates aldosterone
   secretion. Blocking its action reduces peripheral vascular resistance (afterload), which lowers
   blood pressure.
3. It partially dilates the efferent glomerular arteriole, which reduces
   interglomerular pressure and slows the progression of CKD. Reducing the aldosterone level
   promotes sodium and water excretion. This can help to reduce venous return (preload), which
   has a beneficial effect in heart failure

Question 25

What are the 4 main indications for ACE- inhibitors?

Answer 25

1. Hypertension: For the first or second line treatment of hypertension, to reduce the risk of stroke, MI and death from cardiovascular disease. 2. Chronic heart failure: for the first line treatment of all grades of heart failure, to improve symptoms and prognosis 3. Ischemic heart disease: to reduce the risk of subsequent cardiovascular events such as MI and stroke 4. Diabetic nephropathy and chronic kidney disease (CKD) with proteinuria: to reduce proteinuria and progression of nephropathy.

Question 26

What are the 3 main contraindications for ACE- inhibitors?

Answer 26

1. Renal artery stenosis or AKI 2. Pregnancy or breastfeeding 3. Although ACE inhibition is potentially valuable in some forms of CKD, lower doses should be used and renal function monitored closely