a. Indications for Diuretic Use. Diuretics can be given to patients with edema
associated with congestive heart failure, cirrhosis of the liver, and early renal disease.
Diuretics may also be administered to control hypertension.
b. Contraindications for Diuretic Use. Do not use diuretics for patients with
late renal disease, pregnancy (the medication crosses the placenta), and
hypersensitivity to the drug.
c. Adverse Effects from Diuretic Use. Included are the following:
dehydration, electrolyte imbalance, and hypokalemia. The condition hypokalemia may
be characterized by smooth and skeletal muscle weakness. The respiratory and
cardiac muscles may be involved. Electrocardiogram (EKG) changes may occur with
cardiac involvement. The patient may need potassium supplements in the form of drug
therapy and/or foods.
TYPES OF DIURETICS AND LOCATION OF ACTION
a. Water--a Diuretic. When given in excess, water can act as a diuretic. At
times, it may be necessary to limit the intake of water, but if, for example, medications
irritate the urinary tract, a higher intake of water can stimulate excretion enough to avoid
any real damage to the urinary tract.
b. Osmotic Diuretics. Certain nonelectrolyte with common attributes have
been grouped together and called osmotic diuretics. Osmotic diuretics can be given in
relatively large quantities. When so given, these diuretics contribute to the osmolality of
plasma, glomerular filtrate, and tubular fluid in the body. Osmosis, osmolality - refers to
the passage of pure solvent from a dilute solution to a concentrated solution. The
dissolve substances solutions are concentrated through a semipermeable membrane
that separates the two solution.
(1) Characteristics of osmotic diuretics. None-electrolyte action in the
kidney depends on the concentration of osmotically active particles in solution. Most
osmotic diuretics resist being changed by metabolism. An osmotic diuretic acts by
decreasing reabsorption of water in the proximal tubule of the kidney due to increased
osmotic pressure. The primary agent is mannitol (OsmitrolR). The chief characteristics
of these diuretics are:
(a) The nonelectrolyte are freely filterable at the glomerulus.
(b) The nonelectrolyte undergo limited reabsorption by the renal tubule.
The nonelectrolyte are pharmacologically inert by conventional