Indomethacin and the response to bumetanide.

Pretreatment of 8 normal subjects with 100 mg indomethacin decreased the response to bumetanide; cumulative 4-hr excretion of sodium due to 1.0 mg of bumetanide was reduced from 276 +/- 22.9 to 202 +/- 20.9 mEq (p less than 0.003). Effects on volume and Cl paralleled those on Na while K excretion was not affected. When response was analyzed as increment in fractional excretion over basal solute excretion determined from separate control studies, indomethacin decreased response, an effect differing from that of indomethacin on the response to furosemide. The importance and mechanism of the difference in the effect of indomethacin on bumetanide and furosemide is not known.