18. Renal Disease Flashcards
Most common causes of renal disease
DM and HTN
Much of the Na, Cl, Ca, and water that are initially filtered out of the blood are reabsorbed in the ___
Proximal tubule
SGLT2 inhibitors work in this part of the nephron
Proximal tubule
In the descending limb of the loop of Henle, ___ is reabsorbed but not ____
Water is reabsorbed but Na and Cl ions
In the ascending limb of the loop of Henle, ___ is reabsorbed but not ____
Na and Cl ions are reabsorbed but not water
If ___ is present __ passes through the walls of the ascending limb and is reabsorbed
ADH, water
ADH is also called ____
Vasopressin
Loop diuretics inhibit ___ pump in the ____
Na-K pump, thick ascending limb of the loop of Henle
Effect of Loop Diuretics
Less Na reabsorption (increased Na conc in filtrate, less water reabsorbed)
Less Ca reabsorption (Ca depletion, long-term use can cause decreased bone density)
____ is involved in regulating K, Na, Ca, and pH
Distal convoluted tubule
Only ~5% of Na is reabsorbed in this part of the nephron
Distal convoluted tubule
Thiazides work in this part of the nephron
Distal convoluted tubule
Which is a stronger diuretic? Thiazide vs loop diuretic
Loop diuretic
Thiazides work in distal convoluted tubule which only reabsorbs 5% Na so diuretic effect is much less
~25% of Na is reabsorbed in this part of the nephron
Loop of Henle, ascending limb
Effect of thiazides diuretics
Increase Ca reabsorption at the Ca pump in the distal convoluted tubule – long-term use can have protective effect on bones unlike loop diuretics
Potassium sparing diuretics work in this part of the nephron
Distal convoluted tubule and collecting duct
Effect of potassium sparing diuretics
Decrease Na and water reabsorption, increase K retnetion
Nephrotoxic drugs list
Aminoglycosides, Amp B, cisplatin, cyclosporine, tacrolimus, vancomycin, loop diuretics, NSAIDs, polymixins, contrast dye
BUN measure nitrogen in urea, waste product of ____ metabolism
protein
Cr is the waste product of ___ metabolism
muscle
CrCl equation
(140-age) / (72 - Scr) * weight (*0.85 if female)
CKD criteria
eGFR < 60
Albuminuria (AER or UACR ≥30)
decreased eGFR or albuminuria for > 3 months
HTN in kidney disease - first-line treatment and notes
ACEi/ARBs, can increase SCr by 30% (d/c if > 30%), increase K (avoid K supplements and salt substitutions), monitor SCr and K
DM in kidney disease - therapies and notes
SGLT2i (cana, dapa, empagliflozin shown to decrease CV events and CKD)
Second line GLP1RA
Finerenone as add-on to SGLT2i and max tolerated ACEi/ARBs if eGFR ≥ 25
Renal Dose Adj Drug List
Aminoglycosides (increase dosing primarily)
Beta-lactam abx (except antistaphylococcal penicillins and CTX)
Fluconazole
Quinolones (except moxifloxacin)
Vancomycin
LMWHs (enoxaparin)
Rivaroxaban, Apixaban, Dabigatran (for AFib)
H2RAs (famotidine, ranitidine)
Metoclopramide
Bisphosphonates
Lithium
Drugs CI in CKD List
CrCl < 60: Nitrofurantoin
CrCl < 50: TDF (tenofovir disoproxil fumarate) containing products (e.g. Complera, Delstrigo, Stribild, Symfi) // Voriconazole IV (due to vehicle)
CrCl < 30: TAF (tenofovir alafenamide) containing products (e.g. Biktarvy, Descovy, Genvoya, Odefsey, Symtuza) // NSAIDs // Dabigatran and Rivaroxaban (DVT/PE)
GFR < 30: Metformin – do not start if GFR ≤ 45
Other: Meperidine, SGLT2i
Monitoring in CKD-MBD
PTH, phosphorus (phosphate, PO4), Ca, and vitD levels
Hyperphosphatemia contributes to chronically elevated ___ levels (secondary ____) and must be treated to prevent bone disease and fractures
elevated PTH levels (secondary hyperparathyroidism)
3 types of phosphate binders
1) aluminum based, 2) calcium based, 3) aluminum calcium free
Aluminum-based phosphate binder examples and important notes
Aluminum hydroxide, rarely used d/t aluminum accumulation (nervous system and bone toxicity)
ADEs: aluminum intoxication, dialysis dementia, osteomalacia, constipation, nausea
Monitor: Ca, PO4, PTH, s/sx aluminum toxicity
Calcium-based phosphate binder examples and important notes
Calcium acetate (Phoslyra), and calcium carbonate (Tums)
Use as first-line
ADEs: Hypercalcemia, constipiation, nausea
Monitor: Ca, PO4, PTH
Hypercalcemia can be problematic with concomitant use of VitD d/t increased calcium absorption
Aluminum+Calcium-free phosphate binder examples and important notes
Sucroferric oxyhydroxide (Velphoro), Ferric citrate (Auryxia), Lanthanum carbonate (Fosrenol)
No aluminum accumulation, less hypercalcemia, but more expensive
Warnings: Iron absorption with ferric citrate, may require dose reduction of IV iron // GI perforation with lanthanum carbonate, contraindicated for GI obstruction, fecal impaction, ileus
ADEs: Velphoro/Auryxia - diarrhea, constipation, black feces // Lanthanum carbonate: N/V/D, constipation, abd pain
Aluminum+Calcium free phosphate binder that is NOT systemically absorbed and important notes
Sevelamer
ADEs: N/V/D
Can lower total cholesterol and LDL by 15-30%
Phosphate binder drug interactions: separate administration from ___, ___, and ___
levothyroxine, quinolones, and tetracyclines
Vit D deficiency occurs when the kidney is unable to hydroxylate vit D to its final active form, _____
1,25-dihydroxy vitamin D
Vitamin D3 (or ____) comes from ___
cholecalciferol, exposure to UV light from the skin
Vitamin D2 (or ____) comes from ____
ergocalciferol, plant sterols and it the primary dietary source of vitamin D
Calcitriol (Rocaltrol) is the active form of ___
vitamin D3
Cinacalcet (or ___) is a calcimimetic that mimics the actions of calcium on the ___ and causes a reduction in ___. Only used in ____ patients.
parathyroid gland and causes a reduction in PTH // dialysis patients
VitD analogs examples and notes
Calcitriol (Rocaltrol), Calcifediol (Rayaldee), Doxercalciferol (Hectorol), Paricalcitol (Zemplar)
Warnings: digitalis toxicity potentiated by hypercalcemia, contraindicated in hypercalcemia and vit D toxicity
ADEs: hypercalcemia, hyperphosphatemia, N/V/D (>10%)
Monitor Ca, PO4, PTH, 25-hydroxy vit D (calcifediol)
Take with food or shortly after meal to decrease GI upset
Calcifediol is prodrug of ___
calcitriol
Calcimimetics increase the sensitivity of calcium-sensing receptors on the parathyroid gland causing decrease in _____
PTH, Ca, and PO4
Calcimimetic examples and notes
Cincalcet (Sensipar), Etelcalcetide (Parsabiv)
Warning: Cinacalcet - caution in pt with hx of seizures, contraindicated in hypocalcemia // Etelcalcetide - hypocalcemia, worsening HF, GI bleeding, decreased bone turnover
ADEs: Cinacalcet - hypocalcemia, N/V/D, paresthesia, HA, fatigue, depression, anorexia, constipation, bone fracture, weakness, arthralgia, myalgia, limb pain, URTIs // etelcalcetide - muscle spasms, paresthesia, N/V/D
Monitoring: Ca, PO4, PTH
As kidney function declines, EPO production ___
decreases
Eryhtropoiesis-stimulating agents (ESAs) have risks, including ___ and ___
elevated BP and thrombosis
ESAs should only be used when Hgb is ___ and d/c if Hgb exceeds ___, as the risk for thromboembolic disease (DVT, PE, MI, stroke) is increased with higher Hgb levels
< 10, exceeds 11
ESAs are only effective if adequate ___ is available
iron
Renal K excretion is increased by ______
hormone aldosterone, diuretics (loops > thiazides), high urine flow (via osmotic diuresis), and negatively charged ions in the distal tubule (e.g. bicarbonate)
With normal kidney function, acute rise in K from a meal would be offset by the release of ___, which causes K to shift into the cells
Insulin
Hyperkalemia symptoms
Muscle weakness, bradycardia, fatal arrhythmias
Drugs that increase K levels
ACEi, aldosterone receptor antagonists, aliskiren, ARBs, canagliflozin, drospirenone-containing COCs, K-containing IV fluids (including parenteral nutrition), K supplements, SMX/TMP, transplant drugs (cyclosporine, everolimus, tacrolimus)
First step for treating severe hyperkalemia is to give _____ to stabilize the heart (prevent arrhythmias)
calcium gluconate (preferred) or calcium chloride
Note: does not decrease potassium, just stabilized myocardial cells to prevent arrhythmias
Hyperkalemia treatment options: shift K intracellularly
Regular insulin+dextrose (dextrose given to prevent hypoglycemia, dextrose stimulates insulin secretion but does not shift K on its own)
Sodium bicarbonate (used when metabolic acidosis is present)
Albuterol (monitor for tachycardia and chest pain)
Hyperkalemia treatment options: remove K
Furosemide
Sodium polystyrene sulfonate
Patiromer
Sodium zirconium cyclosilicate
Hemodialysis
____ (K binder) has higher risk of GI necrosis when administered with sorbitol. Do not use together.
Sodium polystyrene sulfonate (SPS, Kayexalate)
___ (K binder) has warning for hypomagnesemia
Patiromer (Veltassa)
___ is generally the preferred potassium binder d/t fastest onset of action
Sodium zirconium cyclosilicate (Lokelma)
Metabolic acidosis is a result of decreased ability of the kidney to reabsorb ___
bicarbonate
Bicarbonate replacement drug options
Sodium bicarbonate, sodium citrate/citric acid solution (Cytra-2, Oracit)
Sodium citrate/citric acid solution is metabolized to bicarbonate by the liver (may not be effective in liver failure)
Monitor sodium levels
Factors affecting drug removal during dialysis
Molecular weight/size
Vd
Protein-binding
Membrane
Blood flow rate
Drugs with (smaller/larger) molecules are more readily removed in HD
Smaller
Drugs with a (large/smaller) Vd are less likely to be removed by dialysis
large
(high/low) protein-binding drugs are less likely to be removed by dialysis
High
(higher/lower) flux (pore size) and efficiency (surface area) HD filters remove more substances
High
(Higher/lower) HD blood flow rates increase drug removal
Higher
