Diuretic drugs in patients with impaired renal function

In health, the human kidney is capable of maintaining body water, electrolyte, and acid-base equilibrium in spite of wide dietary variation. Renal disease, primary to the kidney or as part of a systemic process, is commonly accompanied by blood pressure elevation or edema, or both. Oral diuretic drugs have won general acceptance as primary therapeutic agents in mild or moderate hypertension and as part of a broader drug program for severe hypertension. Intermittent oral or parenteral diuretic therapy has greatly augmented primary therapy of edema of cardiac, hepatic, and renal origin. Attention has been called to the potential hazard of their use when impairment of renal function is severe; however, restriction is not necessary in the absence of azotemia. Frequent or excessive use of oral or parenteral diuretics is commonly associated with hypokalemic, hypochloremic alkalosis, or other electrolyte disturbances. Potassium depletion may be avoided with concurrent use of aldosterone antagonists. The use of diuretic agents in patients with impaired renal function carries distinct risks of plasma volume depletion or hypotension and further diminution of glomerular filtration. Existing electrolyte and acid-base disorders are easily aggravated. Careful sodium restriction will commonly prevent edema; however, intermittent diuretic therapy can be helpful. Hypertension can be more effectively and safely managed with sodium restriction and sympathetic nervous system inhibitors or vasodilators; however, care must be taken not to lower pressure to the point of diminishing glomerular filtration. Digitalis has proved to be not only ineffectual but also hazardous and thus contraindicated in patients with acute cardiac decompensation and renal failure; such a clinical problem constitutes an ideal indication for the use of furosemide or ethacrynic acid, which will commonly offer prompt symptomatic relief.