Diuretics

Question 1

Nephron and glomerulus

What can pass through?

Answer 1

only small molecules and H20 can pass through

Question 2

Proximal Convoluted tubule

Answer 2

Na+ is reabsorbed which lead to H20 and Cl- to follow

water is permeable

GFR is reduced by 2/3 (65%)

Question 3

Thin ascending

Answer 3

H20 reabsorbed

Question 4

Thick ascending (TALH)

Answer 4

impermeable to water

only Na+/Cl- reabsorbed H20 does not follow

25% of the sodium load is reabsorbed due to concentration gradient

osmolarity is reduced

Question 5

Distal convoluted tubule

Answer 5

impermeable to H20

Na+ reabsorbed; K+ H+ into tubules

Question 6

Collecting duct

Answer 6

Vasopressin and ADH act here
ADH increases permeability of H20 and shifts osmolarity inside cell to be hypertonic

ADH preserved water which makes urine hypertonic

Question 7

Where does Carbonic Anhydrase Inhibitor act?

Answer 7

Proximal convoluted tubule

Question 8

Carbonic Anhydrase Inhibitor drug

Answer 8

Acetazolamide Oral 500mg BID

Question 9

Carbonic Anhydrase Inhibitor

MOA:
Net effect:
Clinical use:
Side effects:

Answer 9

MOA: inhibits C.A.; resulting in more bicarbonate in the urine
Net effect: alkaline urine due to Na+ (bicarbonate)
Clinical use: alkaline urine, reduce IOP (glaucoma), manage seizures, mountain sickness
Side effects:metabolic acidosis, increase in K+

Question 10

where do Osmotic diuretics act?

Answer 10

Proximal convoluted tubule and thin ascending

Question 11

Osmotic diuretics

MOA:
Net effect:
Clinical use:
Side effects:

Answer 11

MOA: inhibits Na+ and H20 reabsorption
Net effect: increasing the urine osmolarity by forcing Na+ and H20 to stay in urine , increase urine production
Clinical use: treatment for dialysis disequilibrium , reduce IOP and ICP
Side effects: volume overload , contraindicated in cardiac failure

Question 12

Osmotic diuretic drug

Answer 12

Mannitol injection 1-5mg

filtered but no reabsorbed

Question 13

Loop diuretics

MOA:
Net effect:
Clinical use:
Side effects:

Answer 13

MOA: inhibit the Na+/K+/2Cl- symporter, inhibits the ability for macula dense to “sense” NaCl , stimulates biosynthesis of prostaglandins , maintain GFR by increasing renin release (constricts efferent art which increases filtration)

Net effect: most potent class in mobilizing NaCl, significant loss in NaCl, Increase urinary excretion of K+/H+, increase exertion of Mg+ and Ca+, impair the ability of kidney to concentrate urine (b/c TAHL is compromised)
Clinical use: cardiac, renal, hepatic edema, acute pulmonary edema

Question 14

Loop Diuretics Therapeutic Use

Answer 14

Edema: cardiac , hepatic, renal organ IF GFR IS 30 OR BELOW

Pulmonary edema: Decreases pulmonary wedge pressure causing venodilation resulting in decreasing left ventricle filling pressure .
Increase compliance of palm. vasculature that helps stop the fluid

Hypercalcemia: mobilize Ca2+

Protects against renal failure: urine production

Washout toxins

Antihypertensive diuretics with other drugs (severe hypertensive )

Question 15

Loop Diuretic Drugs

Answer 15

Furosemide
Bumetanide
Torsemide
Ethacrynic acid

Question 16

Furosemide

Pharmacological effect

Response time and pharmacokinetics

Answer 16

SULFONAMIDE type drug inhibits NaCl reabsorption in TAHL

dose curve is influenced by renal disease ( kidney disease give them higher dose)

Wide margin safety

Pharmacological: significant loss of NaCl, increase urinary excretion of K+/H+, increase exertion of Mg+ and Ca+, increase renal prostaglandins (inhibit reabsorption of sodium meaning sodium stays in urine), increase venous capacitance (dilate veins)

Pharmacokinetics:
response is 30 minute, last ~ 8 hrs
short half life
excreted in urine 65%