10-04-2006, 05:21 PM
23. A 64-year-old male presents to his primary
care doctor with complaints of lower extremity
edema. He has a history of long-standing
congestive heart failure and has used diuretic
agents in the past to control his edema. He also
has a history of calcium oxalate kidney stones.
Which of the following agents is potentially
useful for the treatment of both these conditions?
(A) Bumetanide
(B) Ethacrynic acid
© Furosemide
(D) Hydrochlorothiazide
(E) Spironolactone
(D) is correct. Thiazide diuretics, such as
hydrochlorothiazide, are hypocalciuric. These agents
decrease the amount of calcium excreted in the urine
and are therefore useful in patients who are prone to
the formation of calcium-containing kidney stones.
Additionally, these diuretics have a role in the treatment
of mild congestive heart failure and hypertension.
Explanation A: No. Bumetanide is a loop diuretic.
These agents are hypercalciuric, increasing the amount
of calcium excreted in the urine.
Explanation B: No. Ethacrynic acid is a loop diuretic.
These agents are hypercalciuric, increasing the amount
of calcium excreted in the urine.
Explanation C: No. Furosemide is a loop diuretic.
These agents are hypercalciuric, increasing the amount
of calcium excreted in the urine.
Explanation E: No. Spironolactone is an aldosterone
antagonist. These agents have a neutral effect on the
urinary excretion of calcium.
24. A 43-year-old male presents to his primary
care doctor with complaints of increasing
abdominal girth. He has a long history of
alcohol abuse and recently stopped drinking.
Spironolactone is prescribed to aid the control
of the patient™s increasing ascites. Which of the
following is the site of action of spironolactone?
(A) Ascending loop of Henle
(B) Collecting duct
© Descending loop of Henle
(D) Distal tubule
(E) Proximal tubule
(D) is correct. Spironolactone is a competitive
aldosterone receptor antagonist. Its site of action is
the late distal tubule where it decreases sodium entry
into cells and increases potassium excretion, promoting
sodium and water loss with preservation of plasma
potassium. Spironolactone is especially useful for
patients with hepatic failure, as it counteracts the
chronic hyperaldosteronism in these patients.
Explanation A: No. The ascending loop of Henle is
the site of action of loop diuretics such as furosemide
and bumetanide.
Explanation B: No. The collecting duct is not the usual
site of action of diuretics.
Explanation C: No. The descending loop of Henle is
not the usual site of action of diuretics.
Explanation E: No. The proximal tubule is the site of
action of carbonic anhydrase inhibitors such as
acetazolamide.
care doctor with complaints of lower extremity
edema. He has a history of long-standing
congestive heart failure and has used diuretic
agents in the past to control his edema. He also
has a history of calcium oxalate kidney stones.
Which of the following agents is potentially
useful for the treatment of both these conditions?
(A) Bumetanide
(B) Ethacrynic acid
© Furosemide
(D) Hydrochlorothiazide
(E) Spironolactone
(D) is correct. Thiazide diuretics, such as
hydrochlorothiazide, are hypocalciuric. These agents
decrease the amount of calcium excreted in the urine
and are therefore useful in patients who are prone to
the formation of calcium-containing kidney stones.
Additionally, these diuretics have a role in the treatment
of mild congestive heart failure and hypertension.
Explanation A: No. Bumetanide is a loop diuretic.
These agents are hypercalciuric, increasing the amount
of calcium excreted in the urine.
Explanation B: No. Ethacrynic acid is a loop diuretic.
These agents are hypercalciuric, increasing the amount
of calcium excreted in the urine.
Explanation C: No. Furosemide is a loop diuretic.
These agents are hypercalciuric, increasing the amount
of calcium excreted in the urine.
Explanation E: No. Spironolactone is an aldosterone
antagonist. These agents have a neutral effect on the
urinary excretion of calcium.
24. A 43-year-old male presents to his primary
care doctor with complaints of increasing
abdominal girth. He has a long history of
alcohol abuse and recently stopped drinking.
Spironolactone is prescribed to aid the control
of the patient™s increasing ascites. Which of the
following is the site of action of spironolactone?
(A) Ascending loop of Henle
(B) Collecting duct
© Descending loop of Henle
(D) Distal tubule
(E) Proximal tubule
(D) is correct. Spironolactone is a competitive
aldosterone receptor antagonist. Its site of action is
the late distal tubule where it decreases sodium entry
into cells and increases potassium excretion, promoting
sodium and water loss with preservation of plasma
potassium. Spironolactone is especially useful for
patients with hepatic failure, as it counteracts the
chronic hyperaldosteronism in these patients.
Explanation A: No. The ascending loop of Henle is
the site of action of loop diuretics such as furosemide
and bumetanide.
Explanation B: No. The collecting duct is not the usual
site of action of diuretics.
Explanation C: No. The descending loop of Henle is
not the usual site of action of diuretics.
Explanation E: No. The proximal tubule is the site of
action of carbonic anhydrase inhibitors such as
acetazolamide.