Diuretics

Question 1

Carbonic Anhydrase inhibitors (1)
Site of action
MOA (3)
Side effects (2)

Answer 1

Acetazolamide
Site: Proximal convoluted tubule
MOA: inhibit carbonic anhydrase, increase H+ reabsorption, block Na+/H+ exchange
SE: hyperchloremic metabolic acidosis, sulfa allergy

Question 2

Given that HCO3- and H+ are found in the tubular fluid, how does carbonic anhydrase affect their concentrations/what happens to them

Answer 2

HCO3- and H+ combine in the tubular fluid (carbonic acid) and are broken down by CA into H20 and CO2.
These diffuse into tubular cells.
CA combines them and breaks them down back to HCO3- and H+
H+ is excreted via H+-ATP-ase and a Na+/H+ antiporter (Na+ in and H+ out)
HCO3- is reabsorbed into blood via HCO3-/Cl- antiporter and a Na+/HCO3- symporter

Question 3

Osmotic agents (1 is a medication, the other not so much)
Site of action
MOA
SE

Answer 3

Mannitol and Urea
Acts on entire tubule
MOA: increase tubular osmolarity (pulls fluid in)
SE: pulmonary edema d/t CHF and anuria

Question 4

Loop agents (4)
Site of action
MOA

Answer 4

Furosemide, ethacrynic acid, bumetanide, torsemide
Site: Ascending loop of Henle
MOA: inhibits Na+/K+/2Cl- transporter

Question 5

Side effects of Loops
Fluid (1)
Metabolic derangement (1)
Electrolytes (3)
2 strange ones, and 1 more that doesn't apply to ethacrynic acid

Answer 5

• Water loss (although this is kinda the point)
• Metabolic ALKALOSIS
• Low K+, Low Ca++, and low Mg++
• Ototoxicity and hyperuricemia
• Sulfa allergy doesn’t apply to EA

Question 6

Thiazide Diuretics (2)
Site of action
MOA

Answer 6

HCTZ and chlorothiazide
Site: Distal convoluted tubule
MOA: Inhibit Na+/Cl- transporter

Question 7

Side effects of thiazides:
Fluid 
Metabolic derangement
Electrolytes (3)
Substances (2)
Two other side effects

Answer 7

Water loss
Metabolic ALKALOSIS
Low Na+, low K+, HIGH Ca++
hyperglycemia, Increased uric acid
Sulfa allergy, pacreatitis

Question 8

Potassium sparing diuretics (3)
Site of action
MOA (2)

Answer 8

Spironolactone, triamterene, amiloride
Cortical collecting tubule
Spironolactone: aldosterone antagonist
Triamterene and amiloride: block sodium channel

Question 9

Side effects of K+-sparing diuretics:
metabolic derangement
electrolyte imbalance (1)
the main one (esp. spironolactone)

Answer 9

Metabolic ACIDOSIS
Increased K+
Antiandrogen effects (gynecomastia with spironolactone)