['Anaesthesia and surgery alter renal function. Inhibition of prostaglandin synthesis by non-steroidal anti-inflammatory drugs (NSAIDs) administered with anaesthesia may further compromise renal function.', 'To study the effects of tenoxicam (NSAID) administered immediately prior to anaesthesia on renal function in normal individuals undergoing routine surgery.', 'A randomised single blind placebo controlled study comparing tenoxicam (40 mg intravenously) with placebo was carried out in 20 healthy (ASA I) patients undergoing lower spinal surgery. Glomerular filtration rate (GFR) was determined by creatinine clearance and renal tubular function measured as osmolar and free water clearance.', 'GFR fell by 60% at the end of surgery but returned to pre-operative values by six hours post-operatively. There was no difference between placebo or tenoxicam with regard to changes in GFR. Tubular function was not altered by tenoxicam.'] Does tenoxicam alter renal function during anaesthesia in normal individuals?