Diuretics, Renal meds, and Lytes Flashcards
Where does NaCl reabsorption primarily occur?
Proximal tubule
What diuretics work primarily on the proximal tubule?
CAI’s and Osmotics
What is the role of the loop of henle?
Concentration of urine
What is the difference b/w the descending and ascending loop of henle?
Descending: water is reabsorbed and NaCl diffuses in
Ascending: water stays in and NaCl ACTIVELY reabsorbed
What diuretics work primarily on the loop of henle?
Loop diurectics
What is the role of distal convoluted tubule?
Reabsorption
What diuretics work primarily on the DCT?
Thiazides
What is the role of the collecting duct?
Final concentraient of urine
What meds work on the collecting duct?
Potassium-sparing diuretics
Vasopressin
2 definitions of Chronic kidney disease
Kidney damage > 3 months defined by structural or functional abnormalities with or without decreased GFR
Or
GFR <60ml/min for > 3 months with or without kidney damage
difference b/w acute and chronic kidney damage
Acute is < 3 months
Chronic is > 3 months
Stage I kidney disease
GRF > 90ml/min
Stage II Kidney disease
GFR 60-89 ml/min
Stage III Kidney disease
GFR 30-59 ml/min (Moderate)
Its less than 60, so its where CKD begins
Stage IV kidney disease
GFR 15-29 ml/min (severe)
Stage V kidney disease
GFR < 15 ml/min (Kidney failure)
Stage VI kidney disease
Dialysis
At what stage of CKD are meds starting to be renally adjusted?
Stage 3
What criteria is use to diagnose acute kidney disease
RIFLE criteria
RIFLE criteria is based on ___
GFR
Pre-renal injury is usually due to ____
dehydration (occurs before the kidney)
Intrinisic renal injury is usually due to ___
medications (large molecules)
causes damage along the nephron
Post-renal injury is usually due to ____
obstruction (kidney stone, growth)
What is FENa?
Fractional Excretion of Na
FENa levels for pre-renal, intrinsic, and post-renal
Pre-renal: <1%
Instrinic: <1.3%
Post-renal: <1.5%
What is the most common carbonic anhydrase inhibitor?
Diamox (Acetazolamide)
What are carbonic anhydrase inhibitors primarily used for?
Glaucoma and altitude sickness
MOA of carbonic anhydrase inhibitors?
Inhibit CA, which inhibits H+ secretion in the proximal tubule. Bicarb and sodium are blocked from reabsorption.
Effect is short lived due to compensation at loop of Henle.
CAI’s cause a loss of Bicarb, which leads to ____
Hypokalemic metabolic ACIDOSIS
Tolerance to CAI’s usually develops after ____
2-3days
Main SE’s of CAI’s
- PONV/GI upset
- Blurred vision leading to confusion and agaitation
Not too worried about fluid shifts
Examples of osmotic diuretics
Mannitol
Urea
MOA of osmotic diuretics
large molecules result it movement of water through osmosis
What major electrolyte abnormality can occur with osmotic diuretics?
hypernatremia
due to loss of water an reduced intracellular volume
Giving mannitol to a a patient with poor myocardial function can results in ___
CHF
What diuretics can be given to for differential diagnosis of acute oliguria?
Mannitol
Loops
Mannitol is only nephroprotective for which patients?
Renal transplant surgery, less incidence of ARF
no evidence it prevents ARF in other cases (CV surgery, trauma, other transplants, surgery in the presence of liver dz/jaundice)
T/F
Mannitol requires the presence of intact BBB
true
T/F
Mannitol can initially increase ICP if given too rapidly
True
due to vasodilation of intracranial and extra cranial vessels simutaneously
How long should Mannitol be administered to decrease ICP?
Over 10 mins
SE’s of mannitol
pulmonary edema
hypovolemia
electrolyte disturbances
plasma hyperosmolarity
Is urea small/large molecule size
small
T/F
urea can cross BBB
True
What has a greater rebound increase in ICP after administration, mannitol or urea?
Urea
What are two major drawbacks to urea?
high incidence of VTE
Tissue necrosis (not seen with mannitol)
What lab value will change when giving urea?
Increase BUN (due to fluid shifts, NOT ARF)
T/F
Compared to mannitol, urea has more SE and is less effective
True
Examples of Loop diuretics
- Furosemide (Lasix)
- Bumetanide (Bumex)
- Torsemide (Demedex)
- Ethacrynic acid (Edecrin)
MOA of loop diurectics
Inhibits Na and Cl reabsorption in the ascending loop and to a lesser extent in the proximal tubule.
T/F
loop diuretics are the best meds for chronic edema (form CHF and liver dz)
True
DOA of loop diuretics
6-12hrs
what loop diuretic has the worst oral bioavailability?
lasix
Loop diuretics are contraindicated in patients with ___ allergy
sulfa
except Ethacrynic acid (Edecrin)
The only difference b/w loop diuretics is _____
oral bioavailability (no difference IV)
Which loop diuretic is safe in patients with a sulfa allergy?
Ethacrynic acid (Edecrin)
Loop diuretics can lead to what 3 things
Loss of Na and water
Hypokalemic metabolic alkalosis
divalent loss (both K+ and Mg+)
Hypocalcemia
carbonic anhydrase inhibitors can cause hypokalemic metabolic _____, loop diuretics can cause hypokalemic metabolic _____
acidosis
alkalosis
What other med should be ordered along with loop diuretics?
potassium
Which loop diuretic has the highest risk of electrolyte abnormalities?
Lasix
Clinical uses of loop diuretics
- mobilizaiton of edema fluid due to renal, hepatic, or cardiac dysfunction.
- Treatment of increased ICP.
- Treatment of hypercalcemia.
- Differential diagnosis of acute oliguria.
Lasix produces diuresis within __
2-10 mins
Furosemide induced production of prostaglandins (E4) results in renal vaso____ and increased ____.
renal vasodilation and increased RBF
What med can inhibit Furosemide-induced increases in RBF?
NSAID’s
What 3 classes of antibiotics can interact with lasix?
Cephlasporins (nephrotoxicity)
Aminoglycosides (nephrotoxicity)
PCN (higher risk of allergic interstitial nephritis)
T/F
Combination of Furosemide and Mannitol is more effective in decreasing ICP then either drug alone.
True
T/F
Effects of lasix on ICP is affected by intact BBB
FALSE
not affected by alterations in BBB. Mannitol requires a intact BBB
What is more effective in decreasing ICP, mannitol or lasix?
mannitol
What effect is seen if mannitol is given to someone with a disruption in BBB?
rebound intracranial HTN
SE’s of loop diuretics
- fluid/electroly abnormalities (can cause arrhythmias and seizures)
- Acute tolerance (braking phenomenon)
- Deafness/Tinnitus (esp if used with ASA)
- cross-sensitivity with sulfa allergies
- Drug interactions
use caution if giving loop diuretic with what 2 other nephrotoxic drugs
NSAID’s and ACE inhibitors (eps if already hypotensive)
What 5 electrolyte abnormalities can occur with loop diuretics?
Hypokalemia Hypochloremia Hyponatremia Hypomagnesemia Metabolic alkalosis
What is the “braking phenomenon”?
Once the electrolytes get depleted so far, the fluid will stop following the electrolytes (because it would than cause a reverse osmosis)
urine is less concentrated because your peeing everything out, the fluid will start going back into the body because it is so electrolyte dependent
Examples of thiazide diuretics
Chlorothiazide (Diuril) Hydorchlorothiazide (Hydrodiuril) Indapamide (Lozol) Metolazone (Zaroxolyn) Chlorthalidone (Hygroton)
MOA of thiazide diuretics
Compete for the Na-Cl cotransporter in the distal tubule to inhibit reabsorption.
Inhibit only urinary diluting capacity, not concentrating capacity.
Thiazide diuretics lead to what 3 things
- Loss of Na and water
- Hypokalemic metabolic alkalosis
- Increased Ca reabsorption (Hypercalcemia)
What is the difference b/w loop diuretics an thiazide diuretics in regards to calcium?
Thiazides = hypercalcemia
loops = hypocalcemia
What class of diuretics is 1st line treatment for HTN?
Thiazides
loops have too many electrolyte abnormalities
2 specific SE’s seen with thiazide diuretics
Hyperglycemia and hyperuricemia (gout)
Examples of potassium-sparing diuretics
K+ sparing:
Amiloride (Midamor)
Triamterene (Dyrenium)
Aldosterone antagonist:
Spironolactone (Aldactone)
Eplerenone (Inspra)
MOA of K+ sparing potassium diuretics
Amiloride and Triamterene:
Inhibit Na reabsoprtion induced by aldosterone. Inhibit active counter transport of Na and K in the collecting duct
MOA of aldosterone antagonist potassium spring diuretics
Spironolactone and Eplerenone: C
Competes for aldosterone receptor sites in the distal tubule to block Na reabsorption and K secretion
can cause HYPERKALEMIA (esp with spironolactone)
Clinical uses of potassium sparing diuretics
Used for the treatment of refractory edematous states due to:
CHF and Cirrhosis of the liver.
Main SE of potassium-sparing diuretics
Hyperkalemia (esp if used in combo with NSAID’s, ACE inhibitors, and beta blockers)
does not produce hyperglycemia and hyperuremias like thiazides
What form of calcium is preferred to treat hyperkalmia, gluconate or chloride?
Gluconate
chloride is an option if central line is in place
What combo of meds is the quickest way to treat hyperkalmia?
Insulin and dextrose (works in 15-30mins, last 2-6hrs)
When treating hyperkalemia with insulin, when would you not need to dextrose along with it?
If BG >200/250
What is drawback to using kayexalate for hyperkalemia?
takes 4 to 6 hrs to reach the colon where it exerts its actions
Patiromer (Veltassa) and Sodium zirconium cyclosilicate (Lokelma) are newer agents to treat hyperkalemia. Which one is used for acute treatment?
Sodium zirconium cyclosilicate (Lokelma)
onset = 1hr, but takes 48 to mainly see a benefit
What is a draw back to Patiromer (Veltassa)?
give separate from other meds by 3 hours (before and after)
What is a draw back to Sodium zirconium cyclosilicate (Lokelma)?
sustained action up to 12 months
What other med be given to stabilize the cardiac membrane besides calcium?
Magnesium
caution using calcium in patients who are also on dig….can worsen dig toxicity
Calcium levels are dependent on ____
albumin
if low albumin, ca+ will look falsely low
what is a drawback to using albuterol to treat hyperkamlemia?
absorbs systemically
Thiazide diuretics increase the likelihood of ___ toxicity
digoxin
think increased Ca+
Thiazide diuretics can potentiate the effects of ___
non-depolarizing NMB’s
What electrolyte also needs to be corrected along with potassium?
Magnesium
IV calcium lowers/increases the threshold potential of the myocardium
lowers
Should you give bicarb to treat hyperkalemia?
No. Unless they are severely acidotic
What can occur if you treat hyponatremia too quickly?
central pontine demylinosis
permanent
What meds are assoc. with hyponatremia?
Thiazides diuretics Loop diuretics Carbamazepine lithium SSRI's
Hyponatremia should be corrected no faster than ___ in the 1st 24 hours and _____ in 48 hours
6-12 mEq/L
18 mEq/L or less
Presentation of hyponatremia
- Neurologic depression
- Seizures
- Respiratory depression
- Coma
VAPTAN’s (vasopressin receptor blockers) are indicated for ___ and ___ hyponatremia
euvolemic and hypervolemic
When would not want to give a VAPTAN to treat hyponatremia?
If hypovolemic, don’t have the fluid volume to remove….would do more harm
remember vasopressin causes you to hold onto water.
Treatment for hypernatremia
D5
causes of hypercalcemia
Hyperparathyroidism, cancer, thiazides
causes of hypocalcemia
Hypoparathyroidism, renal disease, loop diuretics
If someone has low albumin, how do you calculate their corrected calcium level
Normal albumin level (4) - current albumin level (ex. 2.5) = 1.5
take 80% of that and add it to the Ca+ value that is measured on your BMP and that will give you the corrected calcium level
T/F
If a patient has liver or renal disease, you want to measure their calcium level of the BMP
FALSE
need to use ionized calcium levels (free form of calcium)
Treatment for hypercalcemia
Give fluids to try and dilute out, you can use diuretics (NOT a thiazide diuretic) you can use a loop diuretic
can used meds to treat to osteoporosis (Zoledronic acid, Denosumab and Myocalcin )…..slow down osteoblasts and start holding more Ca+ in the bones
Nasal myocalcin or IV Zoledronic acid à to store it away and get it out of the blood stream
Corticosteroids if start to get symptomatic
Antihypertensive effects from Thiazides is from ______
vasodilation
Emily harped on that is not from fluid movement. Initially there is decreased ECF and decreased CO, but the sustained antihypertensive effect is from vasodilation (takes weeks to months to develop)
T/F
Thiazide diuretics inhibit only urinary diluting capacity, not concentrating capacity
True
be careful bc its easy to think to affects the concentrating capacity bc its site of action is the DCT
