Abstract
Renal osmolal clearance after a standard water load was measured in healthy volunteers. After flurbiprofen, 100 mg by mouth, the osmolal clearance fell by 29 per cent. After frusemide, 40 mg by mouth or 20 mg intravenously, the osmolal clearance increased by 105 per cent and 140 per cent respectively, but following pre-treatment with flurbiprofen, the corresponding increases in osmolal clearance were only 19 per cent and 70 per cent. The antagonism between non-steroidal anti-inflammatory drugs and diuretics, of which this is an example, may be a common and clinically important drug interaction.