Renal 1 Flashcards
Natriuresis
Increases Sodium Excretion
Kaliuresis
Increased Potassium Excretion
Diuretic
Drugs that cause net loss of Na+ and Water in urine
Which Ion is reabsorbed less?
Potassium
What drives reabsorption in the Proximal Tubule
Na+-K+-ATPase of the basolateral membrane creates low cytoplasmic Na+ concentrations for apical passive transport
(Na+ moves from Lumen to Blood)
(K+ moves from Blood to Lumen)
What drives reabsorption in the Loop of Henle
Descending Limb is permeable to water
Thick Ascending Limb is impermeable to water
- Apical Na+/K+/2Cl- cotransporters
–> Na+ Reabsorption
What drives reabsorption in the Distal Tubule
Active transport of Na+ by
- Na+/Cl- cotransporter
Calcium excreted by parathyroid hormone
K+ secreted into Distal Tubule
What drives reabsorption in the Collecting Duct
Na+ reabsorbed by:
- K+/H+ coupled secretion (Controlled by aldosterone)
Water reabsorption controlled by vasopressin
Aldosterone
Primary Endogenous Mineralocorticoid
- Increase Na+ reabsorption
- Increase K+ and H+ excretion
What stimulates Aldosterone release
Low plasma Na+ / High K+ influence Zona Glomerulosa
- Stimulates Aldosterone release
Low Na+ increases Angiotensin II
- Stimulates Aldosterone release
Loop Diuretic
- Examples
Furosemide, Bumetanide
Loop Diuretic
- Use
Most powerful diuretic
Vascular action
- Vasodilation effects are independent of diuresis
Treats serious salt/water overload:
- Acute Pulmonary Edema
- Chronic Heart Failure
Loop Diuretic
- MOA
Inhibits Na+/K+/2Cl- of the TAL
- Binds to the Cl- binding site on the luminal membrane (TAL)
Prevents reabsorption, water and ions stay in the lumen
Loop Diuretic
- Adverse Effects
- Excessive Na+ and Water loss
- Hypovolemia
- Hypokalemia
- Hypocalcemia
- Hyperuricemia (Too much Uric acid - Less Blood volume)
- Hearing Loss (From ion balance loss)
Thiazides
- Examples
Bendroflumethiazide
Hydrochlorothiazide
Related Drugs
- Chlortalidone
- Indapamide
- Metolazone
Thiazides
- Use
Less powerful than loop diuretics
Synergistic with loop diuretics
Treats:
- Hypertension
Thiazides
- MOA
Binds to 2Cl- site of Na+/Cl- co-transporters on the distal tubule
- Increases renin secretion
- Increases natriuresis (Na+ loss)
- Reduces Ca2+ excretion
Thiazide
- Adverse Effects
- Erectile Dysfunction (Reversible, less common with low dose)
- Impaired glucose tolerance (Related to effects on ATPase channels)
- Hypokalemia (Potassium is being secreted)
- Hypercalcemia (Calcium builds up)
Potassium Sparing Diuretics
- Examples
Spironolactone, Eplerenone
Potassium Sparing Diuretics
- Use
Not used by themselves
Combined with loop diuretics and thiazide to prevent hypokalemia
Treats:
- Heart failure
- Resistant essential hypertension
Potassium Sparing Diuretics
- MOA
Aldosterone Antagonists
- Competes with aldosterone for its intracellular response
Inhibits distal Na+ retention and K+ secretion in the collecting tubule
- Sodium stays in lumen
- Potassium stays in blood
Potassium Sparing Diuretics
- Adverse Effects
- Hyperkalemia
Less with Eplerenone
- Gynecomastia
- Menstrual Disorders
- Testicular Atrophy
Other Diuretics
- Examples
Triamterene, Amiloride
Other Diuretics
- Use
Limited use when used by themselves
Combined with loop diuretics and thiazides to prevent hypokalemia
