Sulfonamide diuretics have been reported to decrease arterial responsiveness to pressor amines and to enhance the effects of tubocurarine. Exercise caution in administering curare or derivatives during furosemide therapy. It is advisable to discontinue furosemide one week prior to elective surgery. When Furosemide Injection is used to treat hepatic cirrhosis and ascites, therapy should be initiated in the hospital. The rapid loss of fluid and alteration in serum electrolytes in these patients might precipitate hepatic coma.
Careful observation is mandatory during the period of diuresis.
Excessive diuresis induced by the drug may result in dehydration and reduction of blood volume, with circulatory collapse and with the possibility of vascular thrombosis and embolism particularly in elderly patients. Furosemide may cause electrolyte depletion. Frequent serum electrolyte and CO2 content determinations should be performed during therapy. It is essential to replace electrolyte losses and to maintain fluid balance so as to avoid any risk of electrolyte depletion, hypovolemia, or hypotension. Potassium supplements may be required.