Pharmacology of Diuretics Flashcards
These diuretics cause acidosis.
Carbonic anhydrase inhibitors & potassium-sparing diuretics
What ADR is unique to thiazides?
Hyperglycemia - due to decreased insulin release
These drugs act as ADH antagonists.
Conivaptan, tolvaptan
How does aldosterone promote Na+ reabsorption?
Stimulates expression of ENaC & Na+/K+ ATPase in the collecting ducts
What is the MOA of thiazides?
Inhibit the Na+/Cl- cotransporter in the DCT to increase excretion of Na+ & Cl-. They also cause vasodilation
What are the contraindications for carbonic anhydrase inhibitors?
Hepatic impairment, sulfa allergy
What is the MOA of acetazolamide?
Carbonic anhydrase inhibitor - prevents reabsorption of sodium and bicarbonate
What diuretics carry the risk of sulfa allergy?
Carbonic anhydrase inhibitors, loop diuretics (except ethacrynic acid), thiazides
What is the most commonly administered osmotic diuretic?
Mannitol
This diuretic is associated with gynecomastia and male impotence.
Spironolactone
This is the only loop diuretic that may be used in a patient with a sulfa allergy.
Ethancrynic acid
What are the clinical indications for mannitol?
Increased intraoccular or intracranial pressure, forced renal excretion of substances
Overview of Diuretic Effects.
What is the MOA of furosemide?
Loop diuretic - inhibits the Na+/K+/2CL- transporter in the thick ascending loop. This increases excretion of Na+, K+, Cl-, Ca2+, Mg2+, and H2O
This diuretic may be used as prophylaxis to prevent altitude sickness.
Acetazolamide
Potassium sparing diuretics have two distinct MOAs. What are they and which drugs belong to each?
Aldosterone antagonist - spironolactone, eplerenone
Sodium channel blockers - triamterene, amiloride
NSAIDs decrease the effectiveness of what diuretics?
Loop diuretics & thiazides
What diuretic is associated with otoxicity?
Loop Diuretics (Furosemide)
True/False. Osmotic diuretics lead to loss of water and sodium.
False - osmotic diuretics cause water loss with minimal sodium loss. Hypovolemia, hypernatremia, and hyperkalemia are ADRs of osmotic diuretics.
What serious ADR is associated with ADH antagonists?
Demyelination
What are the commonly used thiazides?
Hydrochlorothiazide, chlorothiazide
These diuretics cause alkalosis and hypokalemia.
Loop diuretics & thiazides
This drug is an ADH agonist to treat diabetes insipidus and von Willibrand disease.
Desmopresin
