Diuretics Flashcards
Define diuretics.
Drugs that enhance renal excretion of salt and water.
How do loop diuretics work, giving an example.
Affect channels on the ascending part of the loop.
Example - Frusemide.
How do thiazide diuretics work, giving an example.
Affect channels on the distal tubule section.
Example - hydrocholorthiazide
Describe the function of the aldosterone inducible Na+/K+ ATPase.
The sodium potassium ATPase is responsible for exchange of sodium INTO tubule and potassium out.
These are aldosterone inducible.
Aldosterone antagonists, such as spironolactone, prevents sodium reabsorption and potassium excretion by blocking this channel.
This is known as potassium sparing way of increasing sodium excretion.
What is the relationship between point in tubule and Na+ reabsorption.
Drugs acting early in the tubule prevent more Na+ reabsorption than those that act later, as the Na+ concentration is higher in early stages.
Rank frusemide, thiazides and aldosterone antagonists in order of potency.
Most potent - frusemide
then, thiazides
then, aldosterone antagonists
In terms of potassium sparing/wasting.
Where do frusemide, thiazides and aldosterone antagonists lie?
Frusemide and thiazides are potassium wasting, increasing K+ excretion along with Na+.
Aldosterone antagonists prevent excretion of K+, and prevent reabsorption of Na+, known as potassium sparing.
How do diuretics (frusemide and thiazides) increase K+ excretion.
Diuretics reduce blood volume through excretion of sodium.
Juxtaglomerular apparatus sense the drop in renal flow, and activates renin-aldosterone pathway.
Aldosterone increases the Na+/K+ ATPase pump, increasing excretion of K+.
