Pharmacology - Diuretics (Exam 4) Flashcards
Used to reduce abnormal accumulation of excess fluid in the body
Diuretics
Diuretics accelerate the rate of ________ formation
urine
What organ do diuretics act on?
Kidney
What is the mechanism of diuretics?
Reduce Na+ and water reabsorption
Increase water excretion
What are the common uses of diuretics?
- Edema
- Hypertension
- Congestive heart failure
What does the kidney filter?
Large quantities of plasma
The only location in the nephron that is NOT impacted by diuretics (ON EXAM)
Glomerulus
What is responsible for water reabsorption by the collecting duct?
Medullary osmotic gradient
What are the 5 main classes of diuretics and their sites of action within the nephron?
- Carbonic anhydrase inhibitors - PCT and PST
- Osmotic diuretics - PCT, PST, thin descending and ascending limb
- Loop diuretics - thick ascending limb
- Thiazide diuretics - DCT
- K+ sparing diuretics - CCT
As you move away from the proximal tubule, diuretics are _________ (more/less) effective
less
Where is the primary site of action for carbonic anhydrase (CA) inhibitors? (ON EXAM)
Proximal tubule
What does carbonic anhydrase do?
Transports HCO3- across membranes
What are CA inhibitors used for? (ON EXAM)
Glaucoma
Acute mountain sickness
What is the suffix for CA inhibitors?
“-amide”
What 3 things do CA inhibitors cause? (ON EXAM)
- Hyperchloremic metabolic acidosis
- Hypokalemia
- Stones
What are the side effects of CA inhibitors? (ON EXAM)
Hyperchloremic metabolic acidosis
Renal stones
Renal K+ wasting
What drug is an osmotic diuretic?
Mannitol (Osmitrol)
Only class of drugs that causes acidosis AND hypokalemia (ON EXAM)
CA inhibitors
What part of the nephron do osmotic diuretics act on?
Proximal tubule
Thin descending and ascending limbs
What is the mechanism of osmotic diuretics?
Produces an osmotic gradient by pulling water into the lumen
Prevents reabsorption of water and solute
Osmotic diuretics are freely filtered by the ________
glomerulus
T/F osmotic diuretics have limited reabsorption and are relatively inert
True
Osmotic diuretics produce rapid _________
diuresis
Osmotic diuretics decrease ________ _________ and increase _________ _________
blood viscosity; blood flow
Which patients CANNOT use Mannitol (Osmitrol)?
Patients with peripheral edema
Which drug is a loop diuretic?
Furosemide (Lasix)
What part of the nephron do loop diuretics work on?
Thick ascending limb
When you think loop diuretic, you should think…
Lose EVERYTHING
(all ions are lost)
What are the side effects of loop diuretics? (5)
- Hypokalemic metabolic alkalosis
- Ototoxicity
- Hyperuricemia, gout attacks
- Hypomagnesemia
- Allergic rxns
Loop diuretics cause interference with ______ reabsorption
Ca2+
What is a concern with loop diuretics?
Kidney stones
What drug works quickly at diuresis, so they are often used when glomerular filtration rate (GFR) is low
Loop diuretics
When are loop diuretics used? (5)
- Edema
- Acute hypercalcemia
- Hyperkalemia
- Acute renal failure
- Anion disease
What are the contraindications of loop diuretics?
Sulfonamide sensitivity
Hepatic cirrhosis
Borderline renal failure
Heart failure
What is the major and minor mechanism of thiazide?
Major: inhibit NaCl transport in DCT
Minor: inhibit CA in proximal tubule
What is the suffix for thiazide diuretics?
“-azide”
“-azone”
How do you distinguish between loop diuretics and thiazide diuretics?
Thiazides INCREASE Ca2+ reabsorption
What are the side effects of thiazide diuretics? (7)
- Hypokalemic metabolic alkalosis
- Hyperuricemia
- Increased Ca2+ reabsorption (can be used for kidney stones)
- Impaired carbohydrate tolerance
- Hyperlipidemia
- Hyponatremia
- Allergic rxns
What are the contraindications of thiazide diuretics?
Hepatic cirrhosis
Borderline renal failure
Heart failure
A patient that has an elevated LDL and decreased glucose tolerance is on which diuretic?
Thiazide
What is thiazide used to treat? (8)
- Edema
- Nephrotic syndrome
- Chronic renal failure
- Glomerulonephritis (as long as GFR is >30-40 mL/min)
- Hypertension
- Osteoporosis
- Diabetic nephropathy (as long as GFR is >30-40 mL/min)
- Ca2+ nephrolithiasis
What drugs are K+ sparing diuretics?
Amiloride
Triamterene
Sprionolactone
T/F K+ sparing diuretics are GREAT at diuresis
FALSE, they do NOT cause a lot of water loss
Amiloride and Triamterene are used in patients that are put on what drug long term? Why?
Lithium, to prevent K+ loss
Which K+ sparing diuretic has a lot of off target effects?
Sprionolactone
What does Sprionolactone competitively inhibit?
Mineralcorticoid receptor
What is Sprionolactone specifically used for?
Primary aldosteronism
Heart failure
Cirrhosis
Sprionolactone has _________ side effects
endocrine
What are the endocrine side effects of Sprionolactone?
Menstrual abnormalities
Gynecomastia
Impotence
Reduced libido
Which diuretic is usually the drug of choice?
Loop diuretics
What can diuretics lead to?
Kidney damage
What is the limitation of CA inhibitors?
Exacerbates metabolic acidosis
What is the limitation of K+ sparing diuretics?
Hyperkalemia
What is the limitation of thiazide diuretics?
Ineffective at low GFRs
Which diuretic blocks the effect of aldosterone on the heart?
Sprionolactone
Which diuretic would be used in someone with bad kidney function (low GFR, elevated serum creatinine, creatinine clearance < 50) and severe congestive heart failure: loop or thiazide?
Loop
Which diuretic would be used in someone with bad kidney function and mild congestive heart failure: loop or thiazide?
Loop
Which diuretic would be used in someone with pretty good kidney function, mild congestive heart failure, and no cirrhosis: thiazide or spironolactone?
Thiazide
Which diuretic would be used in someone with cirrhosis, mild congestive heart failure, and no impaired kidney function?
Spironolactone
Which diuretics can cause kidney stones?
CA inhibitors
Loop
Which diuretics are used to treat kidney stones?
Thiazides
Which diuretic is used to decrease cranial or intraocular pressure?
Mannitol (osmotic diuretic)
Which diuretic causes ototoxicity?
Loop
Which diuretic is used for pulmonary edema and/or decreased renal function?
Loop
Sam is a 67 year old man who has had poorly controlled hypertension for the past 15 years, and now presents with signs of ankle edema, a low GFR and a serum creatinine of 2.5 mg/dL. The most effective drug for producing a diuresis and fall in blood pressure in DM is:
a. acetazolamide (Diamox)
b. furosemide
c. mannitol
d. amiloride
e. hydrochlorothiazide
Sam develops hypokalemia. What drug do you add to his regime?
b. furosemide
add K+ sparing diuretic
Which drug reduces mortality by ~30% in patients with heart failure and liver dysfunction that develops after a myocardial infarction?
a. acetazolamide (Diamox)
b. furosemide
c. spironolactone
d. amiloride
e. hydrochlorothiazide
c. spironolactone
Your 55 year old male patient had a MI a year ago and is showing symptoms of congestive heart failure.
What drug do you put them on? What side effects do you warn them about?
Spironolactone
Impotence
Reduced libido
Gynecomastia
Gertrude is a 65 year old woman that has been diagnosed with hypercalcemia related to a parathyroid hormone secreting tumor. In addition to her chemotherapy what
other drug do you put her on? What side effect do you warn her about?
a. Acetazolamide
b. furosemide
c. spironolactone
d. amiloride
e. hydrochlorothiazide
b. furosemide
Ototoxicity
What diuretic drug acts on the proximal tubule, is not that good at blocking Na+ reabsorption, and but is useful for treatment of glaucoma and acute mountain sickness?
a. Acetazolamide
b. furosemide
c. spironolactone
d. amiloride
e. hydrochlorothiazide
a. Acetazolamide
A diuretic used for tx of hypertension and heart failure that can decrease glucose tolerance, produce hypokalemia (in high doses), aggrevate gout by interfering with uric acid secretion, and produce a small rise in LDL
a. Acetazolamide
b. furosemide
c. spironolactone
d. amiloride
e. hydrochlorothiazide
e. hydrochlorothiazide
A 72 year old man is admitted with a history of heart failure and acute left ventricular myocardial infarction. He has severe pulmonary edema. Which of the following drugs is LEAST likely to prove useful in the treatment of acute pulmonary edema?
a. Bumetanide
b. Furosemide
c. Hydrochlorothiazide
d. torsemide
c. Hydrochlorothiazide
A 50 year old woman has a history of frequent high-calcium renal stones. Which is the most useful agent for the treatment of recurrent calcium stones?
a. Mannitol
b. Furosemide
c. Spironolactone
d. Hydrochlorothiazide
e. Acetazolamide
d. Hydrochlorothiazide
When used chronically to treat hypertension, thiazide diuretics have all of the following side-effects EXCEPT:
a. Reduced blood volume or vascular resistance, or both
b. Maximal impact on blood pressure at doses below the maximal diuretic dose
c. Elevated plasma uric acid and triglycerides
d. Decreased excretion of calcium in the urine
e. Ototoxicity
e. Ototoxicity
A patient with a long history of diabetic renal disease and hyperkalemia and recent onset congestive heart failure requires a diuretic. Which diuretic would be least harmful?
a. Amiloride
b. Hydrochlorothiazide
c. Spironolactone
d. triamterene
b. Hydrochlorothiazide
Which diuretic would you use in a patient with cerebral edema?
Mannitol
Under what conditions do you need to be concerned about using Mannitol?
Active bleeding
A patient comes in with severe hypercalcemia. What therapy should be given?
Loop administered with saline
