Diuretics Flashcards
What is the mechanism of action of acetazolamide?
Acetazolamide inhibits proximal tubule carbonic anhydrase -> increased HCO3- excretion
What are the effects of carbonic anhydrase inhibitors (acetazolamide) on renal function? (list 4)
Prevents the reabsorption of bicarb and Na.
Causes modest diuresis, loss of bicarb and Na.
Metabolic alkalosis
Renal compensatory mechanisms limit both the diuretic effect and Na loss
What are the therapeutic uses of Acetazolemide (Carbonic anhydrase inhibitors)? list 3
- Glaucoma, to reduce intraocular pressure.
- Epilepsy
- Altitude sickness
Not often used for diuretic effect.
What are the drug interactions of carbonic anhydrase inhibitors (acetazolamide)?
Decreases the elimination of amphetamines due to increase in urinary pH
What are the toxicities of carbonic anhydrase inhibitors (acetazolamide)? list 4
- Metabolic acidosis (renal effect)
- sedation and paresthesias (CNS effects)
- Bone marrow suppression
- Allergic rxn
3 and 4 due to structural similarity to sulfa drugs
What is the mechanism of action of Furosemide?
Blocks Na/K/Cl symporter in the thick ascending loop of Henle.
Note: must be secreted in the proximal tubule to be effective. Also there is a decrease in Mg and Ca reabsorption
What are the effects of high ceiling (loop) diuretics on renal function?
- Profound diuretic effect
- Significant loss of Na and K
- Loss of Ca and Mg
- Hypokalemia due to actions at distal nephron
- Uric acid excretion is reduced (competes for proximal tubule secretion)
What are the therapeutic uses of loop diuretics (furosemide)? List 5 primary, 2 secondary
- Edema associated with renal failure
- Ascites
- Nephrotic syndrome
- Pulmonary edema
- Heart failure
- HTN, secondline
- Hypercalcemia
List 5 electrolyte effect and 2 side effects of loop diuretics.
- Hyponatremia
- Hypokalemia
- Hypocalcemia
- hypochloremia
- hypomagnesemia
- Hypotension
- Volume depletion
What are side effects and toxicities of loop diuretics (furosemide)
- Hypotension
- Volume depletion
- Ventricular arrhythmias due to hypokalemia
- Ototoxicity
- Muscle weakness due to hypokalemia
- Hypersensitivity rxn due to similarity to sulfa drugs.
List 5 potential metabolic side effects of furosemide.
- Hyperuricemia
- Hyperglycemia
- Increased triglyceride and cholesterol levels
- increased LDL cholesterol
- Decreased HDL cholesterol
List 5 drug interactions of furosemide.
- Antiarrhythmic drugs and cardiac glycosides
- Aminoglycoside antibiotics (cisplatin) - increase likelyhood of ototoxicity
- NSAIDs blunt action of loop diuretics
- Loop diuretics reduce efficacy of gout drugs.
Thiazide Mechanism of action (Hydrochlorothiazide, Chlorthalidone)?
Block Distal Tubule Na/Cl symporter. Must be secreted in proximal tubule.
What are renal effects of Hydrochlorothiazide and Chlorthalidone?
- Na and Cl excretion
- Modest diuresis
- Hypokalemia
- Uric acid excretion is reduced.
- Ca excretion is decreased.
- Mg excretion is increased.
What are therapeutic uses of Hydrochlorothiazide and Chlorthalidone?
HTN
intially thiazides decrease plasma volume.
long term use is associated with a decrease in peripheral vascular resistance.
What are side effects of Thiazides? (Hydrochlorothiazide and Chlorthalidone)
- Hypotension
- Volume depletion
- Hypokalemia
- Hyponatremia
- hypochloremia
- hypercalcemia
- hypomagnesemia.
What are the metabolic side effects of Thiazides? (hint lipid profile)
- Hyperuricemia
- Hyperglycemia
- Increased TGs and Cholesterol
- Increased LDL
- Decreased HDL
What are drugs interactions of Thiazides?
- Antiarrhymthmic drugs and cardiac glycosides
- NSAIDs blunt action of thiazides
- Increase plasma Lithiium levels
- Reduced efficacy of gout drugs.
Are are the 2 classes of K sparing diuretics?
- Na channel inhibitors: amiloride, triamterene
2. Aldosterone receptor antagonists: spironolactone, eplerenone
What are the therapeutics uses of Na-Channel inhibitors? (amiloride, triamterene)
- Modest diuretic effect
- Used to minimize K loss and potentiate the actions of diuretics used to treat HTN or edema
- Not used alone to treat edema or HTN
What is a potential toxicity of Amiloride and Triamterene?
Hyperkalemia
What are the therapeutic uses of Aldosterone antagonists? (spironolactone and eplerenone)
- Modest diuretic action
- Minimize K losses and potentiate actions of other diuretics used to treat edema and HTN
- Improve outcomes in heart failure
What are potential toxicities of Spironolactone and Eplerenone?
Hyperkalemia
Spironolactone: gynecomastia, decreased libido, impotence in men, menstrual irreg./hair growth in women
Eplerenone: ^ SE less likely
Name 2 ACE inhibitors
Lisinopril, Captopril
