Diuretics Flashcards
how are diuretics classified?
Site of action
mechanism of action
What are the types of diuretics?
Thiazides Loop Osmotic Aldosterone Antagonists Carbonic Anhydrase Inhibitors K+ Sparing
What is the mechanism of action and site of action of thiazide diuretics?
Mechanism of Action Inhibit Na and Cl reabsorbtion Site of Action Ascending loops of Henle What really happens? ↑ excretion of ions ↓ K+ ↓ extracellular fluid volume
What are the clinical uses of thiazides?
Essential HTN (alone or in combo)
Edema
Diabetes Insipidus**
Hypercalcemia**
how do thiazides exert their antihypertensive effect?
Initially, ↓ extracellular fluid volume
↓ cardiac output
Long term, peripheral vasodilation
What are the side effects of thiazides?
HYPOKALEMIC, HYPOCHLOREMIC METABOLIC ALKALOSIS Cardiac Dysrhythmias Hypokalemia Hypovolemia Orthostatic hypotension Hyperglycemia Hyperuricemia Renal/hepatic failure
What are 2 examples of loop diuretics?
Ethacrynic acid
Furosemide
How do loop diuretics work?
Inhibit ion reabsorption in the medullary portion of ascending limbs of loop of Henle
What are clinical uses of loop diuretics?
Mobilization of edema
Treatment of ICP
Differential diagnosis of oliguria
-pt must be normal volemic and good kidneys before you give it
NOT treatment for essential HTN
What are the side effects of loop diuretics?
Fluid and electrolyte imbalance -Hypokalemic metabolic alkalosis Hypokalemia ↑ Digitalis toxicity Potentiate NMB drugs Hyperuricemia Aminoglycoside toxicity Sulfonamide allergy
What are some characteristics and MOA of osmotic diuretics?
Freely filterable at the glomerulus Undergo limited reabsorption Resist metabolism Pharmacologically inert Mechanism of Action ↑ osmolarity of renal tubular fluid and prevents reabsorption of water ↑ plasma osmolarity
What are clinical uses for osmotic diuretics?
Prophylaxis against renal failure
-before cross clamp if clamped above renal artery
Differential Diagnosis of oliguria
Treatment of Increased ICP
Reduction of Intraocular pressure
What are the side effects of osmotic diuretics?
Pulmonary edema
Hypovolemia
Electrolyte imbalanc
Plasma hyperosmolarity
What is the dose for mannitol?
0.25-1 g/kg
What are examples of K sparing diuretics?
Tiamterene
Amiloride
Where do k sparing diuretics work?
convoluted tubules
What are the clinical uses of K sparing diuretics?
used in place of or in combo with other diuretics
What is the side effect of K sparing diuretics?
hyperkalemia
What is an example of an aldosterone agonist?
spironolactone
What is the use of aldosterone antagonists?
usually only hepatic failure/ascites
What is an example of carbonic anhydrase inhibitor? What does it do?
acetazolamide
inhibits CA in proximal tubules/inhibits naHCO3 reabsorbtion
What are the clinical uses of carbonic anhydrase inhibitors?
Eye surgery-decrease production of vitreous humor-> decrease IOP
What is the onset time and dose of Lasix?
Onset: 2-10 min
Dose: 0.1 - 1 mg/kg
How much Lasix is needed to increase urine output?
Only 10 mg or 1cc
