Failure of indomethacin to impair the diuretic and natriuretic effects of the loop diuretic torasemide in healthy volunteers.

The effects of torasemide, a new potent loop diuretic, on renin release, water and sodium excretion were investigated in young healthy volunteers before and after 3 days of treatment with indomethacin. Torasemide 20 mg i.v. induced a rapid and biphasic increase both in plasma renin activity and plasma angiotensin II levels, which was almost completely abolished by pretreatment with indomethacin. Torasemide also increased urine volume, sodium excretion and, during the first hour after dosing, the creatinine clearance. None of the latter effects was impaired by indomethacin pretreatment. It is concluded that, like other loop diuretics, torasemide stimulates renin release by increasing renal prostaglandin production. However, at variance with what is observed with other loop diuretics, the diuretic and natriuretic effects of torasemide as well as the change in creatinine clearance do not appear to be inhibited by indomethacin.