Kidney PHARM Flashcards
Function of the Kidney
- Control extracellular fluid volume and composition
- acid-base balance
- excrete wastes (metabolites, drugs)
- Hormones
Indication
Diuretics
- Hypertension
- Fluid volume overload
- heart failure
- kidney failure
- cirrhosis - prevent kidney failure
% electrolyte reabsorption
Different parts of nephron
- Proximal convoluted tubule
- 65% sodium reabsorption
- 100% potassium and bicarb reabsorption - Loop of henle
- 20% sodium reabsorption - early distal convoluted tubule
- 10% sodium reabsorption - late distal convoluted tubule
- 1-5% sodium reabsorption
*water follows
Strongest diuretics act earliest in the nephron
3 basic functions of the nephron
- Filter
- reabsorption
- secretion
Filter
- non selective
- glomerular filtration membrane
- water, electrolytes, a.a., glucose, medication, waste
Reabsorption
- selective
- electrolytes, water, glucose, a.a
Secretion
- selective
- Active process using pumps
- waste, metabolites, glucose, potassium, sodium, etc.
Diuretic, action site on nephron, % blockage
Mannitol
- proximal convoluted tubule
- 65% sodium/chloride blockage
Loop diuretics
- thick ascending loop of henle
- 20% sodium/chloride blockage
Ex. furosemide
Thiazide diuretics
-Early distal convoluted tubule
- 10% sodium/chloride/potassium blockage
Potassium Sparing Diuretics
- late distal convoluted tubule
- 1-5% sodium/chloride blockage
- Ex. spironolactone/triamterene
MOA Diuretics
Blockage passive absorption of water through blocking sodium/chloride reabsorption
*water passively follows sodium reabsorption
AE Diuretics
Excess diuresis
- hypovolemia
- low blood pressure
- dehydration
Excess sodium/chloride blockage
- Hyponatremia
- hypokalemia
- digoxin and lithium toxicity
Classification of Diuretics
- Loop diuretics
Ascending thick limb of henle
Ex. furosemide
20% block Na/Cl reabsorption - Thiazide diuretics
early distal convoluted tubule
Ex. hydrochlorothiazide
10% block Na/Cl reabsorption - Potassium sparing diuretics
late distal convoluted tubule
Ex. spironolactone (aldosterone antagonists)
Ex. triamterene (non-aldosterone antagonists) - Mannitol
Proximal convoluted tubule
65% sodium/chloride blockage
strongest diuretic
Examples
Loop diuretics
Furosemide
Torsemide
Ethancrynic acid
Bumetadine
MOA
Loop Diuretics
Prevention sodium/chloride reabsorption in ascending loop of henle (20% blockage)
Prevents passive reabsorption of water
Promotes diuresis
SE
Loop Diuretics
Excessive diuresis and dehydration
- thirsty, oliguria, dry mouth, weight loss
Hypotension
- diuresis
- vascular smooth muscle relaxation
Ototoxicity
- furosemide reversible
- ethancrynic acid irreversible
Dyslipidemia
- increase LDL, cholesterol, TG (bad)
- decrease HDL
Hyperglycemia
- increase glucose reabsorption
Hyperuremia
- increase urea reabsorption
Electrolyte imbalances
- Hyponatremia
- Hypochloremia
- Hypokalemia (distal convoluted tubule, reabsorbs sodium, excretes potassium)
Drug interactions
Loop diuretics
Digoxin toxicity
- hypokalemia -> dysrhythmias
Lithium toxicity
- increase reabsorption
NSAIDS
- nephrotoxicity
Ototoxic drugs
- ototoxicity and hearing loss
- Ex. aminoglycoside antibiotics
- Ex. misoprostol
Contraindications
Loop diuretics
- Hyponatremia
- Hypochloremia
- Hypokalemia
- Caution: diabetics, dyslipidemia, gout, lithium, digoxin (heart failure), ototoxic drugs, NSAIDs, anti-hypertensives
Therapeutic monitoring
Loop diuretics
Weight (water loss)
electrolytes (sodium, chloride, potassium)
S&S hypokalemia
Blood pressure
Heart rate
S&S hypokalemia
- muscle weakness
- palpitations / dysrhythmias
- numbness, tingling
- constipation
- nausea, vomiting