Potassium Sparing and Osmotic Diuretics

Question 1

Direct sodium channel inhibitors and aldosterone receptor antagonists

Answer 1

Direct - amiloride, triamterene

aldosterone receptor antags - sprinolactone and eplerenone

Question 2

Site and mech of action of Na channel blockers

Answer 2

Block luminal uptake of Na…therefore secretion of K blocked and K is spared

Question 3

Na channel blocker therapetuci use

Answer 3

Modest diuretic

Not usually used alone to tx edema or HTN

Used to minimize K loss from thiazide or loops and can help with HTN or edema

Question 4

Toxocity of Na chennl blockers

Answer 4

Hyperkalemia

Question 5

Alodosterone antagonist mech and site

Answer 5

aldosterone normally Binds to nuclear receptor to stimulate transcription and translation of Na channel and Na/K/ATPase

This blocks that

K is spared

Question 6

Aldosterone antagonist therpaeutic uses

Answer 6

Modest diuretic action and used to minimize K losses…can help with HTN or edema

Especailly helpful with HF

Question 7

Aldosterone antagonists Toxicity

Answer 7

Hyperkalmeia

Sprinolactone - hynecomastia, decreased libido and impotience in men with menstrual irregulairities in women

Eplerenone is less likely to produce these effects

Question 8

Osmotic diuretics site and mech

Answer 8

Mannitol

Freely filterable but not reabsorbed

Increase in osmotic pressure in tubular lumen so increase inruine outflow and electrolyte loss

Also extract H2O from systemic body compartments

Question 9

Osmotic diuretics uses

Answer 9

Mannitol poorly abosrbed and must be given IV

Expansion of ECV increase renal blood flow

Can also tx increase intraocular pressure in glaucoma and reduce cerebral edema

Question 10

Toxocity of osmotic diuretics

Answer 10

Increase in ECV could exacerbate CHF or pulmonary congestion

Also dehydration