Class 12 Deck 1 Flashcards
What are the 4 uses for thiazide diuretics?
- HTN
- Edema
- Diabetes incipidus
- hypercalcemia
How does thiazides help HTN?
- Diuresis, naturesis
- Vasodilate
- Allows for a decrease in other more potent anti-hypertensives, decreasing side effects
What is the MOA of thiazides? and where does it work?
- Inhibit reabsorption of Na and Cl
- CORTICAL Ascending loop
Thiazides increase urinary excretion of what?
- Na
- Cl
- Bicarb
- K
What is the INITIAL anti-hypertensive effect of thiazides?
- Decrease extracellular volume
- Decrease CO
What is the SUSTAINED anti-hypertensive effect of thiazides?
- peripheral vasodilation
- Takes weeks to develop
What are the electrolyte side effects of thiazides?
- hypokalemia, hypochloemic metabolic alkalosis
- Hyperglycemia
- Hyperurecemia
What is the cardiac side effect of thiazides?
-Dysrhythmias due to hypokalemia and hypomag
What are the other side-effects of thiazide induced hypokalemia?
- Muscle weakness
- Ileus
- Nephropathy
- Dig toxicity
- potentiation of non-depolarizing muscle relaxants
When would you suspect decreased intravascular fluid volume?
- Othostatic hypotension
- Hemoconcentration (↑ crit and BUN)
- Decreased filing pressures
What causes the decrease in renal and hepatic function with thiazides?
-Decreases in blood flow to these organs
What is the MOA of loop and where does it work?
- Inhibit reabsorption of Na and Cl
- MEDULLARY Ascending loop
What is the onset of action with Lasix or ethacrynic acid?
-2-10 minutes IV
How is lasix related to GFR?
-Higher the GFR, greater the effect of lasix
Furosemide-induced increases in RBF are inhibited by what?
NSAIDS
Furosemide induced production of _______ results in renal ___________ and ________ RBF
- Prostaglandins
- vasodilation
- Increased
Ethacrynic Acid information?
- Higher GI reactions w/ PO
- Protein bound
- Excreted by kidneys
Furosemide information?
- 90% protein bound to albumin
- Elimination half life is <1hr (short duration of action)
Loop clinical uses?
- Edema
- ICP
- Inhibit calcium uptake for hypercalcemia
- Diagnosis of oliguria
When are loops non-effective?
- HTN
- Will not accelerate elimination of other drugs
- No increase in GFR or tubbular secretion
With loops, what precedes diuresis?
-vasodilation (may drop BP)
With loops, _______ _______ ______ provides prompt effects in the management of acute pulmonary edema.
Decreased venous return
Loops, _______ _________ flow through the throacic duct.
-Increases lymph
How do loops decrease ICP?
- Systemic diuresis
- Decrease in CSF production
- Resolve cerebral edema by improving cellular water transport
How does lasix compare to mannitol compare in decreasing ICP?
- Lasix is not as effective
- Mannitol will cross BBB if damaged( causing rebound ↑ in ICP), lasix will not
What is the most effect treatment of increased ICP? What is the concern?
- Lasix and mannitol together
- dehydration and electrolyte balance
What electrolyte disturbances are seen with loops?
- HypoK
- Hypochloremia
- Hyponatremia
- Hypomag
- Metabolic alkalosis
Loop diuretics can cause acute tolerance aka ______ ______. This is due to activation of __________ _______. And does what? and is treated how? How to reestablish diuretic effect?
- Braking phenomenon
- Renin-angiotension
- Na and H2O retention w/ loops
- Replenish ECF volume
- Thiazide diuretics
How does loop induced hypoK effect the body?
- Dig toxicity
- ventricular irritability
- Enhance NDMB
What other effects does loops have?
- Hyperuricemia
- Hyperglycemia (less likely than thiazides)
- Defmess
How does lasix effect antibiotics?
- Aminoglycosides and cephlasporins = Increased risk of nephrotoxicity
- PCN = allergic interstitial nephritis
How does Loops effect lithium?
-Renal clearance is decreased (due to ↓ Na reabsorption)
There can be a cross sensitivity between lasix and what type of drug?
-Sulfonamide nucleus (Sulfas & thiazides)
How does osmotics work?
-Alters the osmolarity of plasma, renal tubular fluid and glomerular filtrate.
What is the site of action of osmotics?
-Proximal renal tubules and loops of henle (both highly permeable to water)
Mannitol information
- Only IV
- Does not enter cells
- Can only be cleared by glomerular filtration
What is the net diuretic effect of osmotics?
-Urinary excretion of Water, Na, Chloride, and Bicarb
What is the effect of osmotics on the renal tubules?
- Increases osmolarity and prevents reabsorption of water
- Urinary excretion of water, Na, Chloride and Bicarb
How does osmotic effect the plasma?
- increases osmolarity, draws fluis from intra cellular to extracellular.
- Expands intravascular volume
How do osmotics redistribute fluid through the plasma?
- Decrease brain bulk
- Increase renal blood flow
What is the negative effect of osmotic’s plasma redistribution?
-CHF in patient w/ poor myocardial function
Mannitol is a scavenger of what? leading to what?
- Oxygen free radicals
- prevention of cellular swelling, and reduction in renal obstruction
What are the 4 clinical uses of mannitol?
- Prophylaxis against renal failure
- Diagnose oliguria
- Decrease ICP and IOP
What is the only procedure in which mannitol has been proven renal protective?
-Renal transplant surgery
How does mannitol diagnose acute oliguria?
- If UO is increased, there is decreased volume
- If UO is unchanged, there is glomerular or tubular problems
How does mannitol effect ICP?
-Will lower ICP by drawing water from the brain and by decreasing CSF
What does mannitol require to reduce ICP?
-Intact BBB
Mannitol is not associated with ______ _______ in ICP, and the brain will eventually _____ to increases in ______ _______. (later doses less effective)
- Rebound increases
- Adapt
- Plasma osmolarity
What need to be done with mannitol administration because of the initial increase in ICP?
- Slow administration
- give with treatment that decrease intracranial volume (Corticosteroids or hyperventilate)
Mannitol can cause vasodilation of vascular smooth muscle, what two things can this cause?
- Increase in cerebral blood volume / ICP
- Decrease BP
What are the side effects of mannitol?
-Precipitate pulmonary edema in CHF patients
-Hypovolemia / electrolyte disturbances
-
How does mannitol effect NMBDs?
Unlike loops and thiazides, mannitol does not effect NMBD
What differentiates urea from mannitol?
- Smaller size
- venous thrombosis and tissue necrosis after extravasation
- Increases in BUN
- Greater rebound ICP
