High dose furosemide in refractory cardiac failure.

High dose furosemide is commonly used in renal failure to induce diuresis but rarely employed in cardiac failure. As furosemide elimination depends largely on renal excretion, drug accumulation with attendant side-effects would be expected to occur more commonly with renal failure than with cardiac failure. Response to a combination of thiazide diuretics and lower doses of furosemide is often unpredictable, ineffective and sometimes hazardous. High dose furosemide (greater than or equal to 0.5 g day-1) was administered for at least four weeks in 24 patients with severe cardiac failure refractory to a lower dose and to other conventional therapy. Mean maintenance dose of furosemide was 0.7 g day-1 and the maximum dose of furosemide averaged 1.3 g day-1. A peak dose of 8 g day-1 was used successfully in one patient. Improvement was observed in all patients when dosage was increased to and above 0.5 g day-1. There were no major side-effects although new-onset gout (4) and tinnitus (1) were reported; hypokalaemia was readily controlled with spironolactone or potassium supplements. Average duration of therapy was 12 months with a maximum of 33 months. High dose furosemide is logical and effective therapy (with other measures) for severe cardiac failure and relatively safe when administered cautiously. The maximum safe dose is probably no less than that used in renal failure.