Diuretics Flashcards
Carbonic Anhydrase inhibitor
Acetazolamide
Osmotic diuretic
Mannitol
Loop diuretics (Na/K/2Cl transporter inhibitor)
Furosemide (lasix)
Na/Cl tranporter inhibitor
Hydrochlorothiazide
ENaC inhibitors (K sparing diuretics)
Amiloride
Antagonist of mineralocorticoid receptor
Sprionalactone
Vasopressin (ADH) Antagonist
Tolvaptan
Diuretic Braking
The process by which the body adapts to diuresis. Diuretics cause a temporal increase in Na and H2O excretion. Compensatory mechanisms decrease excretion, creating a new steady state.
Mechanisms of diuretic braking
Increased sympathetic activity, renin-angiotensin- aldosterone system, ADH release. During Diuresis, a new steady state is reached at a LOWER VOLUME.
Clinical Indications for diuretic therapy
Edema, Hypertension
Location of action of classes of diuretics in the nephron
PT - Osmotic TDLH - K sparing TALH - Loop DCT - Na/Cl blockers CD - ENaC, Mineralocorticoid antagonists, ADH antagonists, Osmotic
Carbonic anhydrase inhibitors mechanism of action.
If you inhibit luminal carbonic anhydrase, you can’t split H2CO3 into H2O and CO2 so it can diffuse into the epithelium of the PCT. This means that you can’t use the Na/H exchanger to pump Na out of the lumen.
Now you have more HCO3- in the lumen, making it more negatively charged. This keeps cations, like Na+ in the lumen.
What happens to urine and plasma if you are on a carbonic anhydrase inhibitor? Why?
You are excreting more HCO3-, so your urine pH and HCO3- increases. Plasma HCO3- decreases and chloride goes up.
Uses of Acetazolamide (CAI)
Reducing intraocular pressure, alkalizing urine to help excrete weak acids, metabolic alkalosis, to pee off the bicarbonate.
Mechanism of loop diuretics
Inhibits Na/K/2Cl SYMPORTER. This causes the positive luminal potential to deminish, decreasing cation reabsorbtion. It also causes hypochloremia, because you can’t reabsorb Cl. Excretion of ALL IONS, except Ca2+ increases, leading to plasma hypochloremia and HYPOKALEMIA.