12 Questions
What is the treatment for patients with increased intracranial pressure?
Osmotic diuretics
What is a common adverse effect of spironolactone?
Gastric upset
Why should potassium-sparing diuretics be used with caution with other medications?
Because they can induce hyperkalemia
What is the mechanism of action of Carbonic anhydrase inhibitors?
Inhibition of carbonic anhydrase
What is a complication of using osmotic diuretics?
Hyponatremia
What is the benefit of maintaining urine flow following acute toxic ingestion of substances capable of producing acute renal failure?
It reduces the risk of dialysis
What is the primary mechanism of action of thiazides?
Impairment of Na+ and Cl- reabsorption in the early distal tubule
What is a common adverse effect of thiazide diuretics?
Hypokalemia
What is the therapeutic use of loop diuretics?
Treatment of Severe Edema, Pulmonary Edema, and acute renal failure
What is the mechanism of action of spironolactone?
Antagonism of aldosterone at intracellular cytoplasmic receptor sites
What is a potential adverse effect of loop diuretics?
Hypokalemia
What is the mechanism of action of triamterene and amiloride?
Blockage of Na+ transport channels
Study Notes
Thiazides (Low Ceiling Diuretics)
- Impair Na+ and Cl- reabsorption in the early distal tubule, increasing Ca reabsorption and K+ excretion.
- Increase urinary excretion of Na+ (5%), Cl-, K+, and water, leading to reduced ECF volume, cardiac output, and blood pressure.
- Therapeutic uses: Treatment of Hypertension, Mild Edema, and Calcium Nephrolithiasis.
- Adverse effects: Hypokalemia, Hypokalemic metabolic alkalosis, Hyperuricemia, Hyperglycemia, and Hyperlipidemia.
Loop Diuretics (Furosemide, Bumetanide, Torsemide, Ethacrynic acid)
- Inhibit the apical Na+-K+-2Cl- cotransporter of the thick ascending limb of the loop of Henle.
- Therapeutic effects: Treatment of Severe Edema, Pulmonary Edema, Acute Renal Failure, and Hypercalcemia.
- Adverse effects: Profound ECFV Depletion, Hypokalemia, Metabolic Alkalosis, Hypomagnesemia, Hypocalcemia, and Ototoxicity.
Potassium-Sparing Diuretics
- Mechanism of action:
- Spironolactone: antagonizes aldosterone at intracellular cytoplasmic receptor sites, preventing Na+ reabsorption and K+ and H+ secretion.
- Triamterene and amiloride: block Na+ transport channels, decreasing Na+/K+ exchange.
- Therapeutic uses: Induction of Diuresis, treatment of Secondary Hyperaldosteronism, Heart Failure, Resistant Hypertension, Ascites, and Polycystic Ovary Syndrome.
- Adverse effects: Gastric upset, Gynecomastia, Menstrual irregularities, Hyperkalemia, Nausea, Lethargy, and Mental confusion.
Osmotic Diuretics
- Mechanism of action: Hydrophilic chemical substances that are filtered through the glomerulus, then undergo little or no reabsorption, resulting in a higher osmolarity of the tubular fluid and osmotic diuresis.
- Therapeutic uses: Treatment of patients with increased intracranial pressure or Acute Renal Failure due to shock, drug toxicities, and trauma.
- Adverse effects: Extracellular water expansion and dehydration, Hyponatremia, and Hypernatremia until diuresis occurs.
Carbonic Anhydrase Inhibitors (Acetazolamide)
- Mechanism of action: Inhibits carbonic anhydrase in the proximal tubular epithelium, decreasing the ability to exchange Na+ for H+ and resulting in a mild diuresis.
- Therapeutic effects: Increased urinary pH and phosphate excretion by an unknown mechanism.
- Adverse effects: Hyperchloremic metabolic acidosis and decreased diuretic efficacy following several days of therapy.
Learn about the mechanism of action of thiazide diuretics, their pharmacological actions, therapeutic uses, and adverse effects. Understand how they affect sodium, potassium, and calcium levels in the body.
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