Diuretics Flashcards
Define Loop Diuretics and give 1 example.
Inhibits the Na K Cl symporter in the thick ascending loop of Henle
eg: Furosemide, Torsemide, Bumetanide
Define Thiazide Diuretics and give 1 example.
Inhibits Na/Cl symporter in the distal convoluted tubules
eg: Hydrochlorothiazide, Chlorthalidone, Indapamide, Metolazone
Define Potassium-Sparing Diuretics and give 1 example.
A&T inhibits epithelial Na channel in the luminal membrane of the collecting tubules and ducts of the nephron
S&E blocks aldosterone from binding onto the mineralocorticoid receptors, decreasing the expression of epithelial Na channels and Na/K-ATPase pumps in the collecting tubules and ducts
eg: Amiloride, Triamterene, Spironolactone, Eplerenone
Clinical indications for Loop Diuretics
1) Acute pulmonary/peripheral edema associated with heart failure, liver cirrhosis, nephrotic syndrome or renal failure
2) Hypertension in patients with renal failure but not in patients with normal renal function
3) Acute hyperkalemia (high K+ ions in blood)
Clinical indications for Thiazide Diuretics
1) Pulmonary/peripheral edema associated with heart failure, liver cirrhosis and nephrotic syndrome or CHRONIC renal failure
2) Hypertension in patients with NORMAL renal function
3) Idiopathic hypercalciuria (spontaneous rise of calcium levels in urine but normal in blood)
4) Nephrogenic Diabetes Insipidus (overproduction of urine → loss of water)
Clinical indications for Amiloride
Amiloride and Triamterene have WEAK diuretic actions. It is often combined with Loop or Thiazide diuretics to “cancel out” the hyperkalemic S/E. Hence, potassium-sparing diuretics are often co-administered with Loop/Thiazide diuretics to ensure blood potassium levels are normal.
Clinical indications for Spironolactone/Eplerenone
1) Congestive Heart Failure (improves survival)
2) Resistant essential hypertension, especially in low renin-hypertension
3) Primary hyperaldosteronism (Conn’s Syndrome)
Contraindications for Loop Diuretics
1) Severe Hypovolemia
2) Severe Hyponatremia
3) Patient sensitivity to sulfonamides
Contraindications for Thiazide Diuretics
Hypersensitivity to sulfonamides and anti-bacterial agents
Contraindications for Potassium-Sparing Diuretics
1) Patients with hyperkalemia
2) Patients taking ACE inhibitors or ARBs/Sartans as they cause hyperkalemia
3) Patients taking potassium supplements
3 Side Effects of Loop Diuretics
1) Hypovolemia → Hypotension → Dizziness
2) Hypokalemia (Activation of RAAS) → Increases risk of cardiac arrhythmias
3) Hyperglycemia (Decreased release of insulin by pancreas caused by hypokalemia)
4) Hyponatremia
5) Hypochloremia
6) Hypomagnesemia
7) Hypocalcemia
8) Hyperuricemia → Gout
9) Ototoxicity (Damage to inner ear; rare) → Tinnitus and vestibular problems
3 Side Effects of Thiazide Diuretics
1) Hypovolemia
2) Hypokalemia
3) Hyperglycemia
4) Hyponatremia
5) Hypochloremia
6) Hypercalcemia
7) Hyperuricemia
8) Hyperlipidemia
9) Erectile Dysfunction
Side Effect of Amiloride/Triamterene
Hyperkalemia (Decreased K+ secretion in the lumen)
3 Side Effects of Spironolactone/Eplerenone
1) Hyperkalemia
2) Gastrointestinal Disturbances (diarrhoea, gastritis, gastric bleeding, peptic ulcers)
3) Metabolic Acidosis (low blood pH due to decreased secretion of H+ into lumen → increases conc of H+ in blood)
3 Side Effects of specifically Spironolactone
(due to it blocking testosterone receptors)
1) Gynecomastia
2) Decreased Libido
3) Impotence
4) Menstrual Irregularities
