Diuretic agents mercurial

SAFETY PROFILE Poison by intravenous, intramuscular, and intraperitoneal routes. Used as a diuretic agent. When heated to decomposition it emits very toxic fumes of Hg, NOx, and Na20. See also MERCURY COMPOUNDS. 

They act on the kidney by depressing the mechanisms that govern the active reabsorption of sodium and chloride ions. They are rapidly excreted by the kidney but their use is hazardous because their action is believed to be due to inorganic mercury ions released by rupture of the carbon-to-mercury bond, probably followed by the firm attachment of the mercury ion to a sulphydryl group of a renal enzyme. The administration of dimercaprol (SO), a strong chelating agent for mercury, removes mercury from the kidney and terminates the diuretic action. It is of interest that Paracelsus used calomel (mercurous chloride) as a diuretic. 

Hemodynamic contributions to diuresis - Almost certainly, conventional diuretics prevent renal reabsorption of electrolytes by interacting with components of tubular cells. However, hemodynamic mechanisms may also be involved. Ethacrynic acid 5 86 furosemide > 7 reduce renal vascular resistance (RVH) and, thereby, enhance renal blood flow (RBF). The Increase In RBF is proportional to the level of RVR when these drugs are administered and occurs primarily in the middle renal cortex. These agents are not vasodilators in the conventional sense since they do not increase blood flow in other vascular beds nor at pressures in the kidney below the autoregulatory range . Moreover, diuresis itself does not explain the effect since thiazides 7 91 r mercurials reduce rather than increase RBF. While the natriuretic effect of ethacrynic acid and furosemide is probably supplemented by the change in RBF, its contribution appears small. Thus, increased RBF can be demonstrated for the duration of natriuresis if urine volume is replaced 2 the more normal circumstance in which a... 

The diuretic activity and pharmacological properties of the organic mercurials and of ethacrynic acid and furosemide are already well-documented. Discussion of these agents will be confined to recent studies pertaining to their biochemical mechanisms of action. 

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