Lecture 6.12: Drugs and the kidney

Question 1

Where do loop diuretics work? Example? How do they work?

Answer 1

Frusemide, works in the ascending loop of henle.

Inhibits Na/K/Cl carriers into cells from lumen, as such, lumen increases Na in distal tubule and osmotic pressure increases.

This results in reduced water reabsorption.

Results in torrential urination, lasts 3-6 hours. Can result in hypokalaemia, alkalosis.

Question 2

Where do thiazide diuretics work? Example? how do they work?

Answer 2

Distal convoluted tubule. Bendrofluazide, hydrochlorothiazide. Thiazide like drug is indapamide.

Inhibits Na/Cl co transporter, so water reabsorption decreases.

Lasts 4-6 hours. Gentle diuretic.

Again, hypokalaemia. Indapamide has less adverse effects. Used in conjunction with loop.

Question 3

Where do potassium sparing diuretics work? Example? how do they work?

Answer 3

Collecting duct and tubules. Spironolactone, amiloride.

Reduces activation of Na channels, and stimulation of Na pumps, so unable to reabsorb water.

Slow onset because mechanism require the synthesis of an Na channel in the first place.

Often used with other diuretics.

Question 4

Where do heavy metals primarily damage the body? What about gentamicin?

Answer 4

Proximal tubule. Apical membrane of proximal tubule.