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Flashcards in Osmotic Diuretics Deck (7):
1

Where do osmotic diuretics exert their effects?

The proximal tubule (~65%)

2

Benefits of osmotic diuretics?

Helps to eliminate intracellular volume

3

Mannitol (Osmitrol)

prototype for osmotic diuretics; also used --> urea, glycerin, and isosorbide

4

MOA of Mannitol?

- non-metabolized 6-C sugar; freely filtered w/ minimal absorption

- Inability to reabsorb the solute keeps water in the PT lumen; this water is delivered to the distal portion of the nephron where much of it is excreted.

- Acts throughout the body to pull water out of cells

- Net effect after administration is to excrete total body water in excess of plasma electrolytes

5

PK of mannitol?

Distributes in EC fluid, must give IV in large amounts sufficient to raise its osmolality (eg 50-200 grams over 24 hours)

- Effects are noticeable within 30-60 minutes, and is eliminated unchanged in urine over 6-8 hrs

6

Adverse effects of osmotic diuretics?

- EC volume is acutely ↑ bc mannitol sucks water out of cells --> can exacerbate HF

- HA, nausea, vomiting, and fluid & electrolyte imbalance can occur

7

Therapeutic uses of mannitol?

- Prophylaxis of RF, keeps some fluid volume in the tubules to prevent them from collapsing when the GFR is very low

- Reduction of intracranial pressure

- Reduction of intraocular pressure (trx glaucoma) when pts don't respond to other therapy