Exam 2: Diuretics Flashcards
What are the conditions that promote the development of edema?
- Altered blood circulation
- Altered blood composition
- inadequate lymphatic drainage
Where does potassium reabsorption occur?
Secretion?
Reabsorption at the proximal tubule
Secretion at the distal tubule and collecting duct
How do thiazide diuretics affect calcium reabsorption?
Increased calcium reabsorption
How do loop diuretics affect calcium and Mg excretion?
Increase calcium and magnesium excretion
Acidic drugs compete for ** excretion, leading to a ** attack.
Uric acid
Gouty
What 3 drugs are carbonic anhydrase inhibitors?
Acetazolamide, Dorzolamide, and Brinzolamide
What is the MOA of Carbonic anhydrase inhibitors?
-Inhibits the CA enzyme and blocks Bicarb production. This leads a decreased availability of H+ for exchange with Na+, resulting in increased Na+ loss
What are the indications for CA inhibitors?
- Glaucoma
- Alkaline urine
- Alkalosis
What are the adverse effects of CA inhibitors?
- Hyperchloremic metabolic acidosis
- Hypokalemia
- Hyperuricemia
- Renal stones
What are the contraindications with CA inhibitors?
- Hepatic cirrhosis
- sulfa hypersensitivity
What are the two loop diuretics?
Furosemide and Ethacrynic acid
What is the MOA of loop diuretics?
- Block the NCKK2 transporters, impairing the concentration and diluting function of the kidney.
- Induce kidney PGs, to decrease salt transport and to Vasodilate
What are the indications for loop diuretics?
- HF
- Pulmonary edema
- Hypercalcemia
- Works well at low GFR
How do loop diuretics relieve pulmonary edema?
Relieve pulmonary congestion by increasing systemic venous capacitance
How do loop diuretics treat hypercalcemia?
Loops decrease reabsorption of Mg and Ca by reducing the K+ gradient
What are the adverse effects of loop diuretics?
- Hypokalemia metabolic alkalosis
- Hypochloremia
- Hypocalcemia and Hypomagnesemia
- Hyperuricemia
- Irreversible ototoxicity
What are the contraindications of loop diuretics?
- Sulfa hypersensitivity
- Aminoglycosides (enhanced ototoxicity)
- Digoxin (loss of K increases toxicity)
What is the main difference between furosemide and ethancrynic acid?
Ethacrynic acid is not a sulfa derivative and can be used in people allergic to sulfa
-Also has the highest risk of ototoxicity
What drug us a thiazide diuretic and what drugs are compounds related to thiazides?
- Thiazide (HCTZ)
- Related compounds: Metalazone and indapamide
What is the MOA of thiazide diuretics?
Inhibition of sodium reabsorption at the early distal tubule by inhibiting the Na/Cl co transporter
What are the indications for thiazide diuretics?
- HTN (causes relaxation of smooth muscle and vasodilation)
- HF
- Nephrolithiasis
- Nephrogenic DI
What are the adverse effects of thiazide diuretics?
Reduced insulin secretion, Hypokalemia metabolic alkalosis, Hyperuricemia, magnesium loss, hyperglycemia, and elevated serum lipids
How do Thiazide diuretics decrease calcium secretion?
- Increase activity of PTH dependent Ca channels
- Not due to PTH, but due to increased luminal Na which leads to increase in cell membrane potential and increased Ca reabsorption
What is different about Indapamide compared to the other thiazides?
Indapamide is excreted by biliary system and is useful in patients with renal insuffiency
- Does not cause increased plasma lipids
- Vasodilation
What are the contraindications for thiazides?
- Sulfa hypersensitivity
- Hypokalemia can precipitate digitalis toxicity
- diabetics, hyperglycemia and carbohydrate intolerance may occur
- Lithium toxicity
Which thiazide diuretic works with a reduced GFR?
Metalazone
What are the two classes of Potassium sparing diuretics?
- Aldosterone antagonists
- Direct inhibitors of Na+ flux
What kind of drug is spironolactone?
Aldosterone antagonists
What is the MOA of aldosterone antagonists?
1) competitive inhibitor of aldosterone, which promotes the excretion of N and retention of K at the late distal tubule and collecting duct
What are the indications for spironolactone?
- edema associated with HF, cirrhosis, and nephrotic syndrome
- Most effective drug for treating hyperaldosteronism
What are the adverse effects of spironolactone?
- Relatively few, occasional GI upset, nausea, vomiting
- Gynecomastia (androgen receptor antagonist
- Occasional hyperkalemia
What are the contraindications for spironolactone?
Hyperkalemia, chronic renal insuffiency, and liver damage
What kind of drug is eplerenone?
Aldosterone antagonist
What is the MOA of eplerenone?
-Same as spironolactone effects at the aldosterone receptor, but less incidence of endocrine related side effects
What kind of drugs are amiloride and triamterene?
Potassium sparing diuretics that are direct inhibitors of Na flux
What is the MOA of Amiloride and triamterene?
-Inhibit the Na/K ion exchange independently of aldosterone, leading to decreased K excretion
What is the main use of potassium sparing diuretics?
Combination with K losing diuretics
What is the DOC or Li+ induced DI?
amiloride
What are the adverse effects of potassium sparing diuretics?
- Hyperkalemia
- nausea, vomiting, leg cramps, dizziness
What are the 4 osmotic diuretics?
Mannitol, isosorbide, Glycerin, and urea
What are the indications for osmotic diuretics?
- prophylaxis of acute renal failure
- decrease IOP
- decreased ICP
- Protect kidney
What is the contraindication for osmotic diuretics?
HF
What is desmopressin and what is it used for?
Synthetic ADH used to treat central DI
What kind of drug is conivaptan?
ADH antagonist
What are the indications for conivaptan?
-treatment of euvolemic or hypervolemic hyponatremia in hospitalized patients (increases Na concentrations and increases free H20 clearance)
Wha are the adverse effects of Conivaptan?
Hypokalemia
- injection site reactions
- orthostatic hypotension
What is the contraindication to conivaptan?
Hyponatremia associated with hypovolemia
What kind of drug is tolvaptan?
ADH antagonist that is similar to conivaptan, but it is a non-peptide V2 vasopressin receptor antagonist
Why do CA inhibitors cause Hyperchloremia?
Na+ loss is in the form of NaHCO3 instead of NaCl
Why are CA inhibitors not used for long term therapy?
The effectiveness of the drug decreases in a few days because accumulation of H+ within the tubule from normal metabolic processes allows the Na/H exchange to take place again, preventing the diuretic effect
What is the MOA of osmotic diuretics?
Filtered, but not reabsorbed by the kidney. Keeps water in the tubules and produces diuresis
What is the MOA of Conivaptan?
Non-peptide V1a and V2 receptor antagonist
