The effects of selective and non-selective inhibition of cyclo-oxygenase on frusemide-stimulated natriuresis.

The relative potency of four non-steroidal anti-inflammatory drugs (NSAIDs) - indomethacin, flurbiprofen, sulindac and piroxicam - in inhibiting frusemide-stimulated natriuresis and creatinine clearance was investigated in a placebo controlled cross-over study using healthy volunteers. All four drugs tested significantly inhibited the action of frusemide and they were equipotent in their effects. If it is accepted that sulindac is renal sparing with respect to inhibition of prostaglandin synthesis, our observations raise two possibilities concerning the underlying mechanism of antagonism: a) that inhibition of renal prostaglandin synthesis is not important; b) that sulindac interacts with frusemide in a manner different from other NSAIDs.