Diuretics Flashcards
what are the loop diuretics
furosemide and torsemide
how do the loop diuretics work
-inhibit Na/K/2Cl (cotransporter) pump in the thick ascending loop hence inhibiting the reabsorption of NaCl
why are loop diuretics called high ceiling diuretics
they are the most efficacious diuretic agent available since thick ascending loop has a large absorptive capacity and no other part of the nephron after it has the same ability
in the presence of loop diuretics, what is occurring with the other ions located in the distal portion of the nephron
- due to inhibition of reabsorption of NaCl, the lumen positive potential created by reabsorption of the K+ (Na/K/Cl pump) is diminished; this potential drives the reabsorption of Mg2+ and Ca2+ so without it, more of these ions are excreted
- also in distal tubule there is an increased exchange of Na+ for K+ so increased excretion of K+ will lead to hypokalemia
what are loop diuretics used to treat
- management of edema associated with heart failure and hepatic or renal disease
- acute pulmonary edema
- hypertension (though not first line for this)
adverse effects of loop diuretics
OH DANG!
Ototoxicity (tinnitus, hearing impairment, etc)
Hypokalemia (cardiac arrhythmias)
Dehydration (acute hypovolemia due to hyponatremia –> hypotension)
Allergy to sulfa
Nephritis (intersitial)
Gout (due to hyperuricemia)
also hypomagnesia and hypocalcemia
what are the thiazides
Chlorthalidone, Hydrochlorothiazide, Metolazone
how do thiazides work
they inhibit NaCl reabsorption in the distal convoluted tubule by blocking the Na/Cl cotransporter
in the presence of thiazides, what is going on with the other ions in the nephron
- increased excretion of K+ from the distal tubule
- increased reabsorption of Ca2+
- mild magnesuria (don’t know why)
what are thiazides used to treat
- mild to moderate hypertension
- edema from heart failure
- hypercalcuria (help with kidney stones)
- nephrogenic diabetes insipidus
- osteoporosis (hypercalcemia effect)
how long does it take for thiazides to work
1-3 weeks since their half life is about 40 hours
adverse effects of thiazides
HyperGLUCS hyperGlycemia hyperLipidemia hyperUricemia hyperCalcemia hyperSensitivity (sulfa allergy)
HypoKNT
hypoKalemia
hypoNatremia
hypoTension (orthostatic hypotension)
what are the potassium sparing drugs
potassium SEAT Spironolactone Eplerenone Amiloride Triameterene
how would you further classify the potassium sparing drugs
spironolactONE and eplerenONE are aldosterONE antagonist
amiloride and triameteren act at same part of the tubule as the above but they block the Na+ channels in the cortical collecting tubule
what spironolactone and eplerenone used to treat
- edema in those with excessive aldosterone excretion or CHF
- hypertension
- primary hyperaldosteronism
- hypokalemia
- cirrhosis of liver accompanied with edema/ascited
- nephrotic syndrome
off label use of spironolactone
female acne and hirsutism
spironolactone has an affinity to what other receptors not including aldosterone hence leading to what issues
progesterone and androgen receptors antagonist leading to gynecomastia, impotence, and menstrual irregularities
adverse effects of spironolactone and eplerenone
spironolactone - gastric upset and peptic ulcers, endocrine effects (gynecomastia, impotence, decreased libido etc), hyperkalemia, metabolic acidosis (H+ excreted in parallel with K+), CNS effects
eplerenone - GI upset and hyperkalemia
potassium sparing diuretic (those in the aldosterone antagonist class) are contraindicated in who?
those who are hyperkalemia
those who are at risk for developing hyperkalemia like those with chronic kidney disease, on other K+ sparing diuretics, ACE inhibitors, ARBs)
why are amiloride and triamterene usually given
for their antikaliuretic effects to offset effects of other diuretics that increase K+ excretion
inhibit ENAC in late distal tubules
advantage of amiloride and triamterene in comparison to spironolactone and eplerenone
they do not depend on aldosterone to exert their effects of being an antikaliuretic
what is triamterene and amiloride metabolized by
triamterene is metabolized by the liver before being excreted by the kidney while amiloride is excreted as an intact drug
adverse effects of triamterene and amiloride
hyperkalemia and hyponatremia
triamterene –> glucose intolerance, renal stones, interstitial nephritis, photosensitivity
TRIAMTERENE GRIP
what is the carbonic anhydrase inhibitor
acetazolamide
what does carbonic anhydrase do
reduction of absorption of HCO3- in proximal convoluted tubule hence decreasing the amount of sodium absorbed there (but it increases the amount of sodium absorbed in the rest of the nephron so not really efficient)
uses of carbonic anhydrase inhibitor
not usually used for its diuretic property since it is not very efficient at that
Glaucoma (decreases formation of aqueous humor)
Mountain Sickness (blood becomes more acid due to excretion of bicarb hence more blood stimulates more ventilation and increased O2 in the blood)
Metabolic Alkalosis
Epilepsy
when is dosing of acetazolamide reduced
in renal insufficiency since it is excreted unchanged in the proximal tubule
adverse effects of acetazolamide
metabolic acidosis, hyponatremia, hypokalemia, renal stones, sulfa allergy, paresthesia, malaise, fatigue, depression
what is an osmotic diuretic
mannitol
what do osmotic diuretics do
expand extracellular fluid volume, decrease blood viscosity, inhibit renin release, and urinary excretion of almost all electrolytes
what is mannitol used for
- reduction of increased intracranial pressure associated with edema
- reduction of increased intraocular pressure
- promotion of urinary excretion of toxic substances
- genitourinary irrigant in transurethral prostatic resection or other transurethral surgical procedures
adverse effects of mannitol
extracellular volume expansion and hyponatremia
tissue dehydration
what type of people is mannitol contraindicated in
those with active cranial bleeding
what is an ADH antagonist
conivaptan
who is conivaptan given to
- euvolemic and hypervolemic hyponatremia in hospitalized patients
- SIADH patient
- heart failure pts when benefit is greater than risk
adverse effects of conivaptan
nephrogenic DI (due to hypernatremia)
infusion site reactions
atrial fibrillations, GI, and electrolyte disturbances
who is conivaptan contraindicated in
hypovolemic hyponatremia
renal failure
what does conivaptan inhibit
CYP 3A4 inhibitor
