Renal Medications Flashcards
What class of diuretics do not require access to the tubular lumen for effective action:
Mineralocorticoid receptor antagonists
What do osmotic pressure gradients determine?
Determine intracellular and extracellular fluid distribution
What do Starling forces determine?
Determine intravascular vs. extravascular distribution (plasma volume vs. interstitial fluid volume)
What are the general classes of diuretics?
- Osmotic diuretics
- Carbonic anhydrase inhibitors
- Loop diuretics
- Thiazides/thiazide-like diuretics
- K+ sparing diuretics
- Aquaretics
Where do osmotic diuretics access the lumen?
Glomerular filtration
Which diuretics gain entrance into the lumen by organic acid transport?
Loop diuretics
Thiazides
Acetazolamide
What are the loop diuretics?
Furosemide
Bemetanide
Torsemide
Where in the nephron tubule does a majority of K+ depletion occur?
Convoluted tubule
What are the two mineralocorticoid receptor antagonists?
Spironolactone
Eplerenone
What are the uses of K+ sparing diuretics?
Hyperaldoseteronism
Hypokalemia
HFrEF
Resistant HTN
What is the MOA of V2 receptor antagonists?
Block AVP action in the late DT and CD
Inhibit urine concentration by preventing AVP-stimulated AQP2 insertion into luminal membrane of principal cells (inhibit water abstraction in DT & CD)
Describe the concept diminished “ceiling” natriuretic effect?
It is often called a high-ceiling diuretic because it is more effective than other diuretics. Furosemide decreases the sodium, chloride, and potassium reabsorption from the tubule. Subsequently, these ions are retained in the renal tubule and presented to the distal nephron.
How do diuretics differ within their class?
Pharmacodynamically equivalent - they differ in potency, not in efficacy
Pharmocokinteically they are different in bioavailability, elimination route, and cost
Agent selection based on PK and cost!
What loop diuretic is preferred for Rx due to being low cost and efficacious?
Furosemide
What electrolyte imbalance is most commonly seen in loop diuretic use?
Hypokalemia
True or False: All loop diuretics are pharmacologically similar when administered at equivalent doses
True
If a patient on a maximal dose of a loop diuretic without effect, should another loop diuretic be trialed?
No, there is no evidence to suggest that another loop would be effective because they are equivalent at similar effective doses
How do you need to utilize diuretics in patients with CKD?
- Altered PK
- Massive diuretic doses frequently required to achieve effective intraluminal diuretic levels
How do you need to utilize diuretics in patients with HF, NS, and cirrhosis?
- Altered PD
- Attenuated responsiveness may require administration of larger effective diuretic doses w/ increased frequency
How can complications associated with aggressive combinatorial diuretic use be minimized?
Careful monitoring of fluid and electrolyte balance
Direct comparison of chlorthalidone and hydrochlorothiazide has found which one to be more effective?
Chlorithalidone
What are the diuretic treatment recommendations for diabetes insipidus?
CDI: dDAVP (oral desmopresin)
NDI: thiazides (except Li+ toxicity: amiloride to reduce Li+ uptake) + dietary solute restriction
What are the diuretic treatment recommendations for hypercalcemia?
Isotonic IVF + Loop diuretics; calcitonin for dialysis
What do Starling Forces determine?
determine intravascular vs. extravascular distribution (plasma volume vs. interstitial fluid volume).
What are the Thiazide diuretics?
Chlorathiazide
Chlorthalidone
Hydrochlorothiazide
Metolazone
What are the K+ sparing diuretics?
Amiloride
Eplerenone
Spironolactone
Triamterene
What are the aquaretics (V2 receptor antagonists)?
Tolvaptan
Laxivaptan
Conivaptan
What diuretic is the ideal starting agent for HTN, chronic edema, or idiopathic hypercacinuria?
Hydrochlorothiazide
What diuretic treats stones in Meniere’s disease?
Hydrochlorothiazide
Is hydrochlorothiazide effective in renal impairment?
No
What is the MOA of thiazide diuretics?
Blocks reabsorption of Na+ and Cl- in the early segment of the distal convoluted tubule incr water retention incr urine
What are the side effects of hydrochlorothiazide?
Hyponatremia, hypochloremia, dehydration, hypotension, hypokalemia, hyperuricemia, hyperglycemia, hypercalcemia
-Incr digitalis and lithium toxicity
-Contra in gout
What is the use of chlorthalidone?
Thiazide like diuretic
- HTN, HF, hypercalcuria, diabetes
What is the PK of chlorithalidone?
Oral or IV admin, but IV use rare
-Long half-life, low bioavailability
-Excreted in urine unchanged
What is the PK of hydrochlorothiazide?
-Oral admin
-Onset 2 hrs
-Absorbed rapidly and eliminated unchanged
What are the side effects of thiazide diuretics?
Hyponatremia, hypochloremia, hypotension, hypokalemia
What are the uses of Metolazone?
-Thiazide-like diuretic
-Usu added to a loop diuretic in tx of edema in HF
-10x more potent than HCTZ
-Safe in renal insuff
What are the uses of Indapamide?
-Thiazide-like diuretic
-HTN and decomp HF
-Not commonly used
What is the MOA of the aquaretics?
Selectively antagonize V2 receptors in collecting ducts
Increases H2O secretion
What are the uses of Tolvaptan
Inpatient hyponatremia in relation to HF or SIADH
What is the use for Conivaptan?
Inpatient hyponatremia
What is the use of Lixivaptan?
Investigational drug for inpatient hyponatremia
What is the adverse syndrome associated with aquretic diuretics?
Osmotic demylemenation syndrome
