dieuretics Flashcards
what is the mechanism of action of diuretics , where does this take place ?
Blockade of sodium and chloride reabsorption
Proximal tubule produces greatest diuresis
what are the different classes of diuretics
Loop: Furosemide
Thiazide: Hydrochlorothiazide
Osmotic: Mannitol
Potassium-sparing: Two subcategories
Aldosterone antagonists (spironolactone)
Nonaldosterone antagonists (triamterene)
most widely prescribed loop diuretic ?
furosemide ( lasix),
mechanism of lasix ?
Acts on ascending loop of Henle to block reabsorption
considerations of lasix ?
has very rapid onset
IV- 5 MINS ( 2 hours effect)
PO- 60 minutes ( 8 hours effect)
useful with renal diseases, still works with less renal function
therapeutic uses of lasix
Pulmonary edema
Edematous states
Hypertension
lasix adverse effects
Hyponatremia, hypochloremia, and dehydration
Hypotension
Hypokalemia
Ototoxicity -rare
interactions of lasix ?
Digoxin( also causes low K +
Ototoxic drugs
Potassium-sparing diuretics
Lithium( increases lithium levels)
Antihypertensive agents
Nonsteroidal anti-inflammatory drugs
is lasix safe in pregnancy ?
no
what are thiazides and how do they compare to loop diuretucs
Maximum diuresis is considerably lower than with loop diuretics
Not effective when urine flow is scant (unlike with loop diuretics
Effects similar to those of loop diuretics
Increase renal excretion of sodium, chloride, potassium, and water
Elevate levels of uric acid and glucose
Maximum diuresis is considerably low
most widely used thiazide
Hydrochlorothiazide [HydroDIURIL]
adverse effects of Hydrochlorothiazide
Hyponatremia, hypochloremia, and dehydration
Hypokalemia
Use in pregnancy and lactation
Hyperglycemia
Hyperuricemia
Impact on lipids, calcium, and magnesium
Hydrochlorothiazide drug interactions
Digoxin
Augments effects of hypertensive medications
Can reduce renal excretion of lithium (leading to accumulation)
NSAIDs may blunt diuretic effect
Can be combined with ototoxic agents without increased risk of hearing loss
potassium sparing diruetcs
commonly used in conjuction with other diuretics if patient has low K+
HARDLY ever used as therapy alone
has aldosterone antagonists( spironolactone) and non aldosterone antgonists ( Triamterene
Amiloride
potassium sparing diuretics uses
Modest increase in urine production
Substantial decrease in potassium excretion
spironolactone mechanism of action
Blocks aldosterone in the distal nephron
Retention of potassium
Increased excretion of sodium
** takes 48 hours to see results
NA/K pumps dont get produced
therapeutic uses of spironolactone
Hypertension
Edematous states
Heart failure (decreases mortality in severe failure)
Primary hyperaldosteronism
Premenstrual syndrome
Polycystic ovary syndrome
Acne in young women
adverse effects of spironolactone
Hyperkalemia
Benign and malignant tumors
Endocrine effects (gynecomastia, impotence, hirsutism, and deep voice
drug interactions of spironolactone
Thiazide and loop diuretics
Agents that raise potassium levels
Triamterene [Dyrenium mechanism of action
Disrupts sodium-potassium exchange in the distal nephron
Decreases sodium reuptake
Inhibits ion transport
Direct inhibitor of the exchange mechanism
therapetuic uses of Triamterene
Hypertension
Edema
Triamterene adverse effects
Hyperkalemia
Leg cramps
Nausea
Vomiting
Dizziness
Blood dyscrasias (rare)
Amiloride [Midamor] mechanism of action
Blocks sodium-potassium exchange in the distal nephron
therapeutic use of midamor
Counteract potassium loss caused by more powerful diuretics
adverse effects of midamor and drug interactions
hyperkalemia, ACE inhibitors; other drugs with hyperkalemia
what are osmotic diuretics ? ( Mannitol)
Promotes diuresis by creating osmotic force within lumen of the nephron
therapeutic uses of osmotic diuretics
Prophylaxis of renal failure
Reduction of intracranial pressure
Reduction of intraocular pressure
considerations for osmotic diuretics
Can move fluid through kidney even if minimal blood
Can pull fluid from edematous brain tissue but cant cross BBB
Is freely filtered at the glomerulus.
Undergoes minimal tubular reabsorption.
Undergoes minimal metabolism.
Is pharmacologically inert
adverse effects of mannitol
Edema
Headache
Nausea
Vomiting
Fluid and electrolyte imbalance
what to do if mannitol crystalizes
preparation needs to be warmed - may happen if exposed to low temperature
how to avoid adverse effects of lasix ?
diet high in potassium
patients taking spironolactone should avoid what
salt substitutes
other loop diruetics ( water pill )
Ethacrynic acid [Edecrin]
Bumetanide [Bumex]
Torsemide [Demadex]
all water pills will cause
Ototoxicity, hypovolemia, hypotension, hypokalemia, hyperuricemia, hyperglycemia, and disruption of lipid metabolism
