No effect of misoprostol on renal function of rheumatoid patients treated with diclofenac

Non-steroidal anti-inflammatory drugs can reversibly decrease renal function in patients with rheumatoid arthritis (RA). To test whether orally administered prostaglandins could mitigate this decrease, we studied the effect of misoprostol in 24 RA patients during treatment with diclofenac in a randomized, placebo-controlled crossover trial. At baseline, 21 patients had a creatinine clearance below 80 ml/min/1.73 m2. The two treatment phases (with either misoprostol, 600 micrograms daily, or matching placebo tablets) were separated by a washout phase in which diclofenac (150 mg daily) was continued. After treatment with misoprostol/diclofenac the glomerular filtration rate was 72 +/- 5 ml/min (mean +/- standard error), and the effective renal plasma flow was 295 +/- 21 ml/min. After treatment with placebo/diclofenac, the corresponding values were 71 +/- 5 ml/min and 296 +/- 21 ml/min, respectively. We concluded that misoprostol has no effect on the renal function of RA patients treated with diclofenac.