- Furosemide (Lasix),bumetanide
(Bumex), and ethacrynic acid (Edecrin) are
"high-ceiling" loop diuretics acting
primarily at the ascending limb of the loop of Henle.
- The effectiveness of these
agents is related to their site of action
because reabsorption of about 30 - 40% of
the filtered sodium and chloride load
occurs at the ascending loop.
- Distal sites are not able to
compensate completely for this magnitude
of reduction of NaCl reabsorption.
- Loop diuretics increase
urinary Ca2+ in contrast
to the action of thiazides.
- Loop diuretics also
increase renal blood flow by decreasing renal
vascular resistance.
- These drugs are rarely
used in the management of hypertension because of
their short duration of action and the
availability of better drugs.
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