Isosorbide osmotic diuretic

Manufacture of vitamin C starts with the conversion of sorbitol to L-sorbose. Sorbitol and xyHtol have been used for parenteral nutrition following severe injury, bums, or surgery (246). An iron—sorbitol—citric acid complex is an intramuscular bematinic (247). Mannitol administered intravenously (248) and isosorbide administered orally (249) are osmotic diuretics. Mannitol hexanitrate and isosorbide dinitrate are antianginal dmgs (see Cardiovascular agents). 

The osmotic diuretics urea and mannitol are administered intravenously (IV), whereas glycerin and isosorbide are administered orally Administration by the IV route may result in a rapid fluid and electrolyte imbalance, especially when these drugs are administered before surgery with the patient in a fasting state ... 

As their name suggests, osmotic diuretics such as mannitol (Osmitrol), isosorbide (Ismotic), and glycerin (Osmoglyn) draw fluid from the tissues of the body through principles of osmosis. Osmotic diuretics are typically given to treat or prevent acute renal failure (kidney failure). They may also be used to relieve intracranial pressure (swelling of the brain) in cases of head injury or hydrocephalus. 

Isosorbide, an osmotic diuretic (1 to 5 mg/kg p.o.), is used for short-term reduction of intraocular pressure from glaucoma. 

ABSORPTION AND ELIMINATION The oral bioavailability, plasma tj, and route of elimination of the available osmotic diuretics are listed in Table 28-3. Glycerin and isosorbide can be given orally mannitol and urea must be administered intravenously. 

Osmotic diuretics are used cautiously in patients with renal or kidney imi>airment or electrolyte imbalance. The osmotic diuretics are Rregnancy Cat iy B (isosorbide) and C (glycerin, mannitol, and urea) dru and must be used cautiously during pr iancy and lactation. Additive hypotensive effects occur when the osmotic diuretics are given witli otlier antihyiiertensive drugs or nitrate. 

Prototypes and Mechanism of Action Mannitol, the prototypical osmotic diuretic, is given intravenously. Other drugs often classified with mannitol (but rarely used) include glycerin, isosorbide, and urea. Because it is freely filtered at the glomerulus but poorly reabsorbed from the tubule, mannitol remains in the lumen and holds water by virtue of its osmotic effect. The major location for this action is the proximal convoluted mbule, where the bulk of isosmotic reabsorption normally takes place. Reabsorption of water is also reduced in the descending limb of the loop of Henle and the collecting tubule. 

Polyols, such as mannitol, sorbitol, and isosorbide, provide this effect. Sugars, such as glucose and sucrose, also can have a diuretic effect by this mechanism. Although not a polyol, urea has a similar osmotic effect and has been used in the past as an osmotic diuretic. 

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