nephrology Flashcards
3 nephron processes
filtration
reabsorption
secretion
What is filtration?
Passes from plasma into the renal tubule
What is reabsorption
Moves back up into the plasma from the tubule
What is secretion?
Moves into the tubule from the plasma
What are 6 uses for diuretics?
Glaucoma Metabolic Alkalosis Acute Mountain Sickness Acute Renal Failure (ARF) Acute Kidney Injury (AKI) Electrolyte imbalances Hypertension
What are 5 ions effected by diuretics?
Na+ Mg2+ Ca2+ Cl- HCO3-
What is the glomerulus?
First stop in the nephron
Blood pressure – controls filtrate formation
No medication sites of action
Filter allows small particles and ions to pass and form the ultrafiltrate
proximal tubules reabsorb what?
65% of NaCl, K+, Ca2+, Mg2+
85% of NaHCO3
Close to 100% of glucose and amino acids
Proximal tubules secrete what?
Site of action?
Organic acid and bases
Site of action
Carbonic anhydrase inhibitors (CAI) proximal tubular
Adenosine antagonist
Carbonic anhydrase Inhibitors (CAI) 3 agents
Acetazolamide (Diamox)
Dorzolamide (Trusopt)*
Brinzolamide (Azopt)
Carbonic anhydrase Inhibitors (CAI) MOA
Inhibits enzyme responsible for dehydration of H2CO3
Reduces aqueous humor production in the eye
Carbonic anhydrase Inhibitors (CAI) indications
Glaucoma, urinary alkalization, metabolic alkalosis, acute mountain sickness
CAI kinetics
Absorbs well: oral and ocular
Increase urine pH; onset 30 min, duration 12 hr, peak 2 hr
Excretion: proximal tubular secretion
CAI contraindication and adverse reactions?
Adverse Reactions
Renal stones, potassium wasting, drowsiness, hypersensitivity reaction
Contraindication
Hepatic cirrhosis
Loop of henle reabsorption
15-25% NaCl, K+
Secondary: Ca2+, Mg2+
Secretion and site of action for loop of henle
Secretion
Some K+
Site of action
Loop diuretics
Loop diuretic agents
Furosemide (Lasix)
Bumetanide (Bumex)
Torsemide (Dexadex)
Ethacrynic acid (Edecrin)
Loop diuretic MOA
Inhibits Na+/K+/2Cl- transporter
indication for loop diuretics
Edema, hypercalcemia, hyperkalemia, anion overdose
kinetics for loop diuretics
Orally well absorbed; duration of action
Torsemide 1 hour; 4-6 hours
Furosemide 2-3 hours; 2-3 hours
adverse effects for loop diuretics
Hypomagnesemia, hyperuricemia, ototoxicity, allergic reaction
Contraindications for loop diuretics
Overuse in hepatic cirrhosis, renal failure, or heart failure
Sulfonamide allergy*
what decreases the effectiveness of loop diuretics
NSAIDs – decrease effectiveness of loop
If your patient had an sulfa allergy related to furosemide, what other loop diuretic could you use
Ethacrynic acid
Conversion of loop diuretics
PO to IV conversion
Furosemide 2:1 (40 mg PO = 20 mg IV)
Torsemide and Bumetanide 1:1
Conversion between agents
Furosemide 40 mg = Torsemide 20 mg = Bumetanide 1 mg
Distal Convoluted Tubule
reabsorption, secretion and site of action
Reabsorption 4-8% of Na+, Cl- Secretion Ca+ by parathyroid control Site of action Thiazide diuretics
2 types of thiazide agents
Hydrochlorothiazide (Hydrodiuril)
Chlorothiazide (Diuril)
MOA of thiazides
Inhibits NaCl transporter
Enhances Ca+ reabsorption