EVALUATION OF THE RENAL PROTECTIVE EFFECT OF MISOPROSTOL IN ELDERLY, OSTEOARTHRITIC PATIENTS AT RISK FOR NONSTEROIDAL ANTIINFLAMMATORY DRUG-INDUCED RENAL DYSFUNCTION

An age greater than 60 and diuretic use have been implicated as risk f actors for nonsteroidal anti-inflammatory drug (NSAID)-induced decreas es in renal function. Misoprostol, a prostaglandin E, analog, was stud ied in nine elderly osteoarthritic patients at risk for NSAID-induced renal dysfunction to determine whether it could prevent NSAID-induced renal dysfunction. Subjects received ibuprofen 2400 mg/day and either misoprostol 800 mcg/day or placebo for 14 days in a randomized, double -blinded, crossover trial. Glomerular filtration rate (GFR) and effect ive renal plasma flow (ERPF) studies using inulin and PAH plasma clear ance, urinary prostaglandin E(2)(PGE(2)) and protein excretion, and se rum electrolytes were obtained at baseline, after the first dose, and on day 7 and 14 of each treatment period. Prostaglandin E(2) excretion was significantly reduced after the first dose of ibuprofen and throu ghout the 14 days in both the misoprostol and placebo treatment groups . No statistically significant differences in GFR, ERPF, protein excre tion, serum potassium, or serum sodium were detected between misoprost ol and placebo treatment during the 14 days of ibuprofen treatment. Ho wever, a subset of two patients who exhibited a decrease of greater th an 20% in GFR during placebo treatment, appeared to demonstrate an att enuation of this decline when treated with misoprostol. Effect of time , independent of treatment group, indicated that ERPF was significantl y decreased from baseline after the first dose of ibuprofen (P less th an or equal to 0.05), whereas GFR was notably diminished from baseline on day 14 only (P less than or equal to 0.05). Misoprostol does not i nfluence GFR and ERPF in unselected subjects purportedly at risk for N SAID-induced renal dysfunction. However, further study is necessary in preselected patients in whom a NSAID-induced decrease in GFR has been documented.