In a double-blind randomized clinical trial the efficacy and safety of oral high-dose
torasemide (1-isopropyl-3- ([4-(3-methyl-phenylamino)
pyridine]-3-sulfonyl)
urea, T)
therapy was compared with that of
furosemide (F) in 10 patients with advanced
chronic renal failure. The efficacy on
edema, fluid and electrolyte balance including the influence on renin-angiotensin-aldosterone system and cochlear function was evaluated. Patients were randomly allocated to either 500 mg F/d (group 1) or 200 mg T/d (group 2). After 14 days of treatment doses were doubled in each group for further 14 days. With respect to the 2.5 times lower dose of T the clinical effect of both drugs on
edema, fluid and
sodium excretion was equipotent. Significant differences were noted on calciuresis. Serum
calcium levels were reduced with F, while T had no influence on
calcium balance. A significant increase in plasma
renin activity (PRA) was observed after F, whereas T had no raising effect on PRA. No significant alteration of plasma
aldosterone concentration occurred with T or F. No adverse effects were noted in both groups. Serial audiometries showed no significant impairment of cochlear function with both drugs. In conclusion, these results indicate that high-dose T is efficient and safe in the treatment of advanced
chronic renal failure. The lack of a calciuric effect with T can be regarded as an advantage in patients with
hypocalcemia in
chronic renal failure.