Antinatriuretic effect of sulfinpyrazone

Clinical observations suggest that sulfinpyrazone (Anturan) may lead to edema formation in borderline compensated cardiac insufficiency. Since the drug is increasingly used in secondary prophylaxis of sudden death after myocardial infarction, a trial was designed to confirm or to refute the suspicion that sulfinpyrazone may interfere with natriuresis. In two experimental series, 18 volunteers were given a sodium load of 5 g or 6 g and natriuresis was first measured at hourly intervals for 4 hours and thereafter for an additional 4-hour period. The experiment was repeated with a single dose of 400 mg sulfinpyrazone given with the sodium load. In the first, non-randomized trial (n = 8) 71.2 +/- 20.7 (SD) mval Na was excreted within 8 hours without, and 41.2 +/- 20.6 mval with sulfinpyrazone (p less than 0.05). In the second, randomized trial (n = 10), sodium excretion fell from 74.2 +/- 38.0 mval/8 h in the control experiment to 43.5 +/- 20.6 mval/8 h after sulfinpyrazone (-42%; p less than 0.05). Excretion of potassium and creatinine remained unchanged. It is concluded that sulfinpyrazone does indeed interfere with normal renal sodium excretion and that the phenomenon may be relevant in patients with borderline compensated myocardial insufficiency. The design of the trial provides a relatively easy way to obtain valuable information on the clinically relevant antinatriuretic side effects of many drugs, particularly that of non-steroidal antiinflammatory agents.