Ethacrynic Sodium Injection and Electrolyte losses

The use of loop diuretics, particularly at high dosages or during chronic therapy, is commonly associated with loss of electrolytes, including potassium, sodium, chloride, magnesium, and calcium. Potassium and magnesium depletion may lead to cardiac arrhythmias and cardiac arrest. Other electrolyte-related complications include metabolic alkalosis and hyponatremia, which are rarely life-threatening. Excessive diuresis, as indicated by rapid weight loss, may induce dehydration and hypovolemia, which can result in acute hypotension, orthostasis, circulatory collapse, vascular thrombosis and embolism, and abrupt reduction in glomerular filtration and renal blood flow. Severe dehydration is most likely to occur in the elderly and patients under prolonged sodium restriction. Therapy with loop diuretics should be administered cautiously in patients with or predisposed to fluid and electrolyte depletion, including patients with primary or secondary aldosteronism (may have low potassium levels); those with severe or prolonged diarrhea or vomiting; and those with poor nutritional status. Fluid and electrolyte abnormalities should be corrected before initiating therapy, and blood pressure as well as serum electrolyte concentrations monitored periodically and maintained at normal ranges during therapy. Patients should be advised to immediately report signs and symptoms of fluid or electrolyte imbalance, including dry mouth, thirst, weakness, lethargy, drowsiness, restlessness, muscle pains or cramps, muscular fatigue, hypotension, oliguria, tachycardia, arrhythmia, or gastrointestinal disturbances such as nausea and vomiting. Digitalized patients and patients with a history of ventricular arrhythmias should be monitored carefully, since the development of hypokalemia may be particularly dangerous in these patients. The risk of hypokalemia may be minimized by slow diuresis, a lower diuretic dosage, potassium supplementation, or combined use with a potassium-sparing diuretic. Similarly, to prevent excessive dehydration and hyponatremia, sodium intake should be liberalized if clinically feasible.