Renal Agents Flashcards
Filter approximately 1300 mL blood per min or 700 mL plasma
Kidneys
In the kidney, the peritubular capillary network surrounds the
Convoluted tubules
Passes close to the glomerulus between the afferent and efferent arterioles
Distal Convoluted Tubule
Osmotic diuretics that promote water retention in the tubular fluid
Mannitol or glucose
Water permeability in collecting duct is controlled by
ADH
Inhibits ADH secretion by the pituitary
Alcohol
A carbonic anhydride inhibitor that blocks sodium bicarbonate reabsorption, resulting in decrease in NaCl reabsorption
Acetazolamide
Acetazolamide functions on the
Proximal tubule
Osmotic agents act on the thin descending limb to promote
Water retention
Block the NKCC2 cotransporter
-Act on thick ascending limb
Loop diuretics (i.e. furosemide)
Relatively impermeable to water
DCT
Blocks the electrically neutral Na+/Cl- cotransporter NCC
Thiazides diuretics
Reabsorption in DCT is via parathyroid hormone regulated apical Ca2 channel and a basolateral Na+/Ca2+ exchanger
Ca2+
The site of mineralcorticoid and ADH action
Collecting tubule
The major site of K+ secretion
Collecting tubule
Sodium bicarbonate reabsorption by the PCT is initiated by the action of the
-Allows Na+ to enter the cell
Na+/H+ exchanger NHE3
Inhibits carbonic anhydride and acts predominantly in the proximal tubule by blocking sodium bicarbonate reabsorption
Acetazolamide
The bicarbonate loss from carbonic anhydride inhibitors can cause a
Hyperchloremic metabolic acidosis
The portion of acetazolamide that can cause allergic reactions, bone marrow depression, and skin toxicity
Sulfonamide group
Carbonic anhydride inhibitors should be avoided in patients with
Hepatic Cirrhosis
Used to treat glaucoma, acute mountain sickness, metabolic alkalosis, and to alkalinize the urine
C.A. Inhibitors
Raise CO2 content of tissues, which in turn stabilizes deoxyhemoglobin
-Useful for counteracting acute mountain sickness
C.A. Inhibitors
Osmotic diuretics such as mannitol act in the
-Where the cells are freely permeable to water
PT and Descending limb of Henle’s loop
Causes loss of water, reduced intracellular volume, and hypernatremia risk
Mannitol
Function to increase water excretion in preference to Na+ excretion
- Reduces intracranial and intraocular pressure
- Promotes prompt removal of renal toxins
Osmotic Diuretics
Water expansion into the extracellular compartment causing hyponatremia
-Effect of osmotic diuretic toxicity
Extracellular volume expansion
Can complicate congestive heart failure and may produce florid pulmonary edema
Extracellular Volume Expansion
Excessive use of osmotic diuretics w/out carefully monitoring serum ion composition and fluid balance can lead to
Dehydration and Hypernatremia
Loop diuretics act in the loop of Henle and block the
NKCC2 cotransporter
Loop diuretics cause an increase in the excretion of
Mg2+ and Ca2+
Furosemide, bumetanide, ethacrynic acid, and torsemide are the
Loop Diuretics
The most effective diuretics currently available
Loop diuretics
A phenoxyacetic acid derivative containing an adjacent ketone and methylene group
Ethacrynic Acid
What is the duration of effect for
- ) Furosemide
- ) Torsemide
- ) 2-3 hours
2. ) 4-6 hours
Block tubuloglomerular feedback by inhibiting salt transport into the macula densa
Loop Diuretics
Induce synthesis of renal prostaglandins by expressing COX-2
Loop Diuretics