loop diuretics

Question 1

what is the reasoning behind the name ‘loop diuretic”

Answer 1

they are diuretics that act at the ascending limb of the loop of Henle in the kidney, hence the loop part of the name.
Diuretics
From the Greek día- through Ouron - urine
through urine.

Question 2

name the individual drugs in this class (loop diuretics)

Answer 2

• E - ethacrynic acid
• T - torasemide
• F - furosemide
• A - azosemide
• B - bumetanide

all end in “ide” except ethacrynic acid

Question 3

what are the indications for loop diuretics?

Answer 3

Mneumonic HeHe

1. HEart failure
   - for symptomatic treatment of fluid overload
2. Hypertension
   - achieve better control of blood pressure in those with resistant hypertension, or in patients with impaired renal function or heart failure.
3. oEdema
   - For relief of breathless in acute pulmonary oedema alongside nitrates and oxygen
   - For symptomatic treatment of fluid overload in oedematous states such as renal failure or liver failure in which case it’s given in conjunction with other diuretics.

Question 4

what is the mechanism of action of loop diuretics?

Answer 4

They work in the loop of henle, specifically on the sodium potassium 2 chloride transporter in the thick ascendíng limb of the loop of henle.

It inhibits the NaKCL2 cotransporter, which means that sodium is not reabsorbed into the blood. Causing an increase in the distal tubular concentration of sodium, reduced hypertonicity of the surrounding interstitium, and less water reabsorption in the collecting duct. This altered handling of sodium and water leads to both diuresis (increased water loss) and natriuresis (increased sodium loss).

Question 5

what are the adverse effects of loop diuretics?

Answer 5

• Dehydration and hypotension due to water loss.
• Hyponatraemia
• Hypokalaemia
• Hypomagnesemia
• Ototoxicity
  
  • Theres a similar cotransporter found inner thne ear that is responsible for regulating endolymph composition. At high doses loop diuretics can affect this and cause hearing loss and tinnitus

Question 6

what are the contraindications of loop diuretics?

Answer 6

• Those patients who are hypovolaemic or dehydrated
• Hepatic encephalopathy patients
• Those with severe hypokalaemia or hyponatraemia.
• Loop diuretics should be avoided taken chronically if patient has gout as they can inhibit Uric acid excretion.

Question 7

what are the interactions of loop diuretics?

Answer 7

Loop diuretics have potential to interact with any drug excreted by the kidneys.

• Lithium concentration increased due to reduced excretion
• Digoxin toxicity may be increased
• Amino glycosides can increase the risk of ototoxicity and nephritis.