diuretics Flashcards
diuresis
increased water loss
what do diuretic drugs do?
- increase urine output
- remove excess fluid
what are they used for?
- hypertension
- heart failure
- edematous states
what are diuretics
drugs that accelerate rate of urine formation (excretion of sodium and water)
can water move out of the nephron on its own?
no; where sodium goes water follows (osmosis)
what parts of the nephron do drugs work
- not proximal tubule
- loop of henle (20-25% reabsorbtion)
- distal convoluted tubule (7% reabsorption)
- collecting ducts (1-2%
negatives of diuretics
- excessive fluid loss (dehydration)
- electrolyte imbalance
- acid-base imbalance
types of diuretics
- loop diuretics
- thiazide (and related) diuretics
- k sparing
loop diuretic example
furosemide
furosemide mechanism of action
- in ascending loop of henle
- inhibit Na transporter
is furosemide high or low ceiling
high ceiling diuretic: significant diuresis and quickly
furosemide indications
- heart failure
- hypertension: reduced venous return and CO (secondary choice)
- hypercalcemia
furosemide adverse effects
- excessive fluid loss (dehydrated and easier to have thrombosis/embolism, low Na/Cl and electrolyte imbalance)
- hypokalemia
- hypoglycemia (diabetes mellitus pt)
hypokalemia symptoms
- decrease in potassium (<3.5mmol/L)
- irregular heartbeat (fatal dysrhythmias)
- muscle weakness/lethargy
- leg cramps
- GI disturbances (constipation)
furosemide interactions
- digoxin (heart failure drug) more toxic with hypokalemia
- can have increased hypokalemia with other diuretics - glucocorticoids
- ototoxicity (ear) with aminoglycosides
- decrease hypoglycemic effect of diabetic drugs
thiazide diuretic example
hydrochlorothiazide (po)
thiazide mechanism of action
- distal convoluted tubule
- inhibit sodium and chloride reabsorption
- affect protein transporter
why are thiazide diuretics low ceiling
less Na reabsorption in this area so drugs have less effect
thiazide indications
- hypertension (first choice drug)
- edema
-indirect: HF, liver cirrhosis
thiazide adverse effects
- hypokalemia
- hyperglycemia (diabetes pt - inhibit insulin secretion)
- genitourinary system (impotence - no penile erection)
thiazide interactions
- digoxin more toxic with hypokalemia
- antidiabetic drugs don’t work at well, lead to hyperglycemia
k sparing diuretic example
spironolactone (aldactone)
spironolactone mechanism of action
- act on collecting ducts
- aldosterone receptor blocker
- affect hormonal control of sodium reabsorption
- block reabsorption of sodium and water usually induced by aldosterone
- reduce sodium-potassium exchange
spironolactone indications
- edema from HF
- hypertension
- reverse potassium loss from other diuretics (combo therapy)
- hyperaldosteronism
